[REF]: Replace the condition 'if not context' with 'if context is None'.

bzr revid: uco@tinyerp.com-20101123070505-9i2lrqhgxzaii3zn

220 files changed, 306 insertions, 1255 deletions

diff --git a/addons/account/account.py b/addons/account/account.py
index 65db73f8d0a..eb60c41ed35 100644
--- a/addons/account/account.py
+++ b/addons/account/account.py
@@ -182,7 +182,7 @@ class account_account(osv.osv):
 
     def search(self, cr, uid, args, offset=0, limit=None, order=None,
             context=None, count=False):
-        if not context:
+        if context is None:
             context = {}
         pos = 0
 
@@ -215,8 +215,6 @@ class account_account(osv.osv):
                 order, context=context, count=count)
 
     def _get_children_and_consol(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         #this function search for all the children and all consolidated children (recursively) of the given account ids
         ids2 = self.search(cr, uid, [('parent_id', 'child_of', ids)], context=context)
         ids3 = []
@@ -310,16 +308,12 @@ class account_account(osv.osv):
             return res
 
     def _get_company_currency(self, cr, uid, ids, field_name, arg, context=None):
-        if not context:
-            context = {}
         result = {}
         for rec in self.browse(cr, uid, ids, context=context):
             result[rec.id] = (rec.company_id.currency_id.id,rec.company_id.currency_id.code)
         return result
 
     def _get_child_ids(self, cr, uid, ids, field_name, arg, context=None):
-        if not context:
-            context = {}
         result = {}
         for record in self.browse(cr, uid, ids, context=context):
             if record.child_parent_ids:
@@ -335,8 +329,6 @@ class account_account(osv.osv):
         return result
 
     def _get_level(self, cr, uid, ids, field_name, arg, context=None):
-        if not context:
-            context = {}
         res={}
         accounts = self.browse(cr, uid, ids, context=context)
         for account in accounts:
@@ -403,8 +395,6 @@ class account_account(osv.osv):
     }
 
     def _check_recursion(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         obj_self = self.browse(cr, uid, ids[0], context=context)
         p_id = obj_self.parent_id and obj_self.parent_id.id
         if (obj_self in obj_self.child_consol_ids) or (p_id and (p_id is obj_self.id)):
@@ -434,8 +424,6 @@ class account_account(osv.osv):
     def name_search(self, cr, user, name, args=None, operator='ilike', context=None, limit=100):
         if not args:
             args = []
-        if not context:
-            context = {}
         args = args[:]
         ids = []
         try:
@@ -499,8 +487,6 @@ class account_account(osv.osv):
         return super(account_account, self).copy(cr, uid, id, default, context=context)
 
     def _check_moves(self, cr, uid, ids, method, context=None):
-        if not context:
-            context = {}
         line_obj = self.pool.get('account.move.line')
         account_ids = self.search(cr, uid, [('id', 'child_of', ids)])
 
@@ -517,8 +503,6 @@ class account_account(osv.osv):
         return True
 
     def _check_allow_type_change(self, cr, uid, ids, new_type, context=None):
-        if not context:
-            context = {}
         group1 = ['payable', 'receivable', 'other']
         group2 = ['consolidation','view']
         line_obj = self.pool.get('account.move.line')
@@ -535,7 +519,7 @@ class account_account(osv.osv):
         return True
 
     def write(self, cr, uid, ids, vals, context=None):
-        if not context:
+        if context is None:
             context = {}
 
         if 'company_id' in vals:
@@ -709,7 +693,7 @@ class account_journal(osv.osv):
     def name_search(self, cr, user, name, args=None, operator='ilike', context=None, limit=100):
         if not args:
             args = []
-        if not context:
+        if context is None:
             context = {}
         ids = []
         if context.get('journal_type', False):
@@ -791,8 +775,6 @@ class account_fiscalyear(osv.osv):
         return True
 
     def _check_duration(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         obj_fy = self.browse(cr, uid, ids[0], context=context)
         if obj_fy.date_stop < obj_fy.date_start:
             return False
@@ -839,7 +821,7 @@ class account_fiscalyear(osv.osv):
     def name_search(self, cr, user, name, args=None, operator='ilike', context=None, limit=80):
         if args is None:
             args = []
-        if not context:
+        if context is None:
             context = {}
         ids = []
         if name:
@@ -871,16 +853,12 @@ class account_period(osv.osv):
     _order = "date_start"
 
     def _check_duration(self,cr,uid,ids,context=None):
-        if not context:
-            context = {}
         obj_period = self.browse(cr, uid, ids[0], context=context)
         if obj_period.date_stop < obj_period.date_start:
             return False
         return True
 
     def _check_year_limit(self,cr,uid,ids,context=None):
-        if not context:
-            context = {}
         for obj_period in self.browse(cr, uid, ids, context=context):
             if obj_period.special:
                 continue
@@ -903,16 +881,12 @@ class account_period(osv.osv):
     ]
 
     def next(self, cr, uid, period, step, context=None):
-        if not context:
-            context = {}
         ids = self.search(cr, uid, [('date_start','>',period.date_start)])
         if len(ids)>=step:
             return ids[step-1]
         return False
 
     def find(self, cr, uid, dt=None, context=None):
-        if not context:
-            context = {}
         if not dt:
             dt = time.strftime('%Y-%m-%d')
 #CHECKME: shouldn't we check the state of the period?
@@ -931,8 +905,6 @@ class account_period(osv.osv):
     def name_search(self, cr, user, name, args=None, operator='ilike', context=None, limit=80):
         if args is None:
             args = []
-        if not context:
-            context = {}
         ids = []
         if name:
             ids = self.search(cr, user, [('code','ilike',name)]+ args, limit=limit)
@@ -941,8 +913,6 @@ class account_period(osv.osv):
         return self.name_get(cr, user, ids, context=context)
 
     def write(self, cr, uid, ids, vals, context=None):
-        if not context:
-            context = {}
         if 'company_id' in vals:
             move_lines = self.pool.get('account.move.line').search(cr, uid, [('period_id', 'in', ids)])
             if move_lines:
@@ -969,8 +939,6 @@ class account_journal_period(osv.osv):
     _description = "Journal Period"
 
     def _icon_get(self, cr, uid, ids, field_name, arg=None, context=None):
-        if not context:
-            context = {}
         result = {}.fromkeys(ids, 'STOCK_NEW')
         for r in self.read(cr, uid, ids, ['state']):
             result[r['id']] = {
@@ -993,8 +961,6 @@ class account_journal_period(osv.osv):
     }
 
     def _check(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for obj in self.browse(cr, uid, ids, context=context):
             cr.execute('select * from account_move_line where journal_id=%s and period_id=%s limit 1', (obj.journal_id.id, obj.period_id.id))
             res = cr.fetchall()
@@ -1007,8 +973,6 @@ class account_journal_period(osv.osv):
         return super(account_journal_period, self).write(cr, uid, ids, vals, context=context)
 
     def create(self, cr, uid, vals, context=None):
-        if not context:
-            context = {}
         period_id=vals.get('period_id',False)
         if period_id:
             period = self.pool.get('account.period').browse(cr, uid, period_id, context=context)
@@ -1068,8 +1032,6 @@ class account_move(osv.osv):
 
         if not args:
           args = []
-        if not context:
-          context = {}
         ids = []
         if name:
             ids += self.search(cr, user, [('name','ilike',name)]+args, limit=limit, context=context)
@@ -1087,8 +1049,6 @@ class account_move(osv.osv):
             ids = [ids]
         if not ids:
             return []
-        if not context:
-            context = {}
         res = []
         data_move = self.pool.get('account.move').browse(cursor, user, ids, context=context)
         for move in data_move:
@@ -1100,8 +1060,6 @@ class account_move(osv.osv):
         return res
 
     def _get_period(self, cr, uid, context=None):
-        if not context:
-            context = {}
         periods = self.pool.get('account.period').find(cr, uid)
         if periods:
             return periods[0]
@@ -1163,7 +1121,6 @@ class account_move(osv.osv):
     }
 
     def _check_centralisation(self, cursor, user, ids, context=None):
-        if not context: context = {}
         for move in self.browse(cursor, user, ids, context=context):
             if move.journal_id.centralisation:
                 move_ids = self.search(cursor, user, [
@@ -1175,7 +1132,6 @@ class account_move(osv.osv):
         return True
 
     def _check_period_journal(self, cursor, user, ids, context=None):
-        if not context: context = {}
         for move in self.browse(cursor, user, ids, context=context):
             for line in move.line_id:
                 if line.period_id.id != move.period_id.id:
@@ -1194,7 +1150,7 @@ class account_move(osv.osv):
     ]
 
     def post(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         invoice = context.get('invoice', False)
         valid_moves = self.validate(cr, uid, ids, context)
@@ -1227,8 +1183,6 @@ class account_move(osv.osv):
         return True
 
     def button_validate(self, cursor, user, ids, context=None):
-        if not context:
-            context = {}
         for move in self.browse(cursor, user, ids, context=context):
             top = None
             for line in move.line_id:
@@ -1253,7 +1207,7 @@ class account_move(osv.osv):
         return True
 
     def write(self, cr, uid, ids, vals, context=None):
-        if not context:
+        if context is None:
             context = {}
         c = context.copy()
         c['novalidate'] = True
@@ -1317,7 +1271,6 @@ class account_move(osv.osv):
         return super(account_move, self).copy(cr, uid, id, default, context)
 
     def unlink(self, cr, uid, ids, context=None, check=True):
-        context = context or {}
         toremove = []
         obj_move_line = self.pool.get('account.move.line')
         for move in self.browse(cr, uid, ids, context=context):
@@ -1335,7 +1288,6 @@ class account_move(osv.osv):
         return result
 
     def _compute_balance(self, cr, uid, id, context=None):
-        context = context or {}
         move = self.browse(cr, uid, [id], context=context)[0]
         amount = 0
         for line in move.line_id:
@@ -1767,7 +1719,7 @@ class account_tax(osv.osv):
         """
         if not args:
             args = []
-        if not context:
+        if context is None:
             context = {}
         ids = []
         if name:
diff --git a/addons/account_analytic_analysis/account_analytic_analysis.py b/addons/account_analytic_analysis/account_analytic_analysis.py
index 064c724a52a..d4ee5428bb9 100644
--- a/addons/account_analytic_analysis/account_analytic_analysis.py
+++ b/addons/account_analytic_analysis/account_analytic_analysis.py
@@ -519,7 +519,7 @@ class account_analytic_account_summary_user(osv.osv):
                 ')')
 
     def _read_flat(self, cr, user, ids, fields, context=None, load='_classic_read'):
-        if not context:
+        if context is None:
             context = {}
         if not ids:
             return []
@@ -695,7 +695,7 @@ class account_analytic_account_summary_month(osv.osv):
                 ')')
 
     def _read_flat(self, cr, user, ids, fields, context=None, load='_classic_read'):
-        if not context:
+        if context is None:
             context = {}
         if not ids:
             return []
diff --git a/addons/account_analytic_plans/account_analytic_plans.py b/addons/account_analytic_plans/account_analytic_plans.py
index abd6c741da0..edb675862ca 100644
--- a/addons/account_analytic_plans/account_analytic_plans.py
+++ b/addons/account_analytic_plans/account_analytic_plans.py
@@ -28,7 +28,7 @@ from tools.translate import _
 
 class one2many_mod2(fields.one2many):
     def get(self, cr, obj, ids, name, user=None, offset=0, context=None, values=None):
-        if not context:
+        if context is None:
             context = {}
         res = {}
         for id in ids:
@@ -115,7 +115,7 @@ class account_analytic_plan_instance(osv.osv):
         return super(account_analytic_plan_instance, self).copy(cr, uid, id, default, context=context)
 
     def _default_journal(self, cr, uid, context=None):
-        if not context:
+        if context is None:
             context = {}
         journal_obj = self.pool.get('account.journal')
         if context.has_key('journal_id') and context['journal_id']:
diff --git a/addons/account_anglo_saxon/stock.py b/addons/account_anglo_saxon/stock.py
index 9e400b00b7f..ad7bba3103e 100644
--- a/addons/account_anglo_saxon/stock.py
+++ b/addons/account_anglo_saxon/stock.py
@@ -31,7 +31,7 @@ class stock_picking(osv.osv):
     def action_invoice_create(self, cr, uid, ids, journal_id=False,
             group=False, type='out_invoice', context=None):
         '''Return ids of created invoices for the pickings'''
-        if not context: context = {}
+        if context is None: context = {}
         res = super(stock_picking,self).action_invoice_create(cr, uid, ids, journal_id, group, type, context=context)
         if type == 'in_refund':
             for inv in self.pool.get('account.invoice').browse(cr, uid, res.values(), context=context):
diff --git a/addons/account_budget/account_budget.py b/addons/account_budget/account_budget.py
index 5287a7fe8f0..590b431a63f 100644
--- a/addons/account_budget/account_budget.py
+++ b/addons/account_budget/account_budget.py
@@ -111,7 +111,7 @@ class crossovered_budget_lines(osv.osv):
     def _prac_amt(self, cr, uid, ids, context=None):
         res = {}
         result = 0.0
-        if not context: context = {}
+        if context is None: context = {}
         for line in self.browse(cr, uid, ids, context=context):
             acc_ids = [x.id for x in line.general_budget_id.account_ids]
             if not acc_ids:
@@ -134,14 +134,14 @@ class crossovered_budget_lines(osv.osv):
 
     def _prac(self, cr, uid, ids, name, args, context=None):
         res={}
-        if not context: context = {}
+        if context is None: context = {}
         for line in self.browse(cr, uid, ids, context=context):
             res[line.id] = self._prac_amt(cr, uid, [line.id], context=context)[line.id]
         return res
 
     def _theo_amt(self, cr, uid, ids, context=None):
         res = {}
-        if not context: context = {}
+        if context is None: context = {}
         for line in self.browse(cr, uid, ids, context=context):
             today = datetime.datetime.today()
             date_to = today.strftime("%Y-%m-%d")
@@ -172,7 +172,7 @@ class crossovered_budget_lines(osv.osv):
 
     def _theo(self, cr, uid, ids, name, args, context=None):
         res = {}
-        if not context: context = {}
+        if context is None: context = {}
         for line in self.browse(cr, uid, ids, context=context):
             res[line.id] = self._theo_amt(cr, uid, [line.id], context=context)[line.id]
         return res
diff --git a/addons/account_coda/account_coda.py b/addons/account_coda/account_coda.py
index b4714045de2..ab3aa8c37f6 100644
--- a/addons/account_coda/account_coda.py
+++ b/addons/account_coda/account_coda.py
@@ -43,7 +43,7 @@ class account_coda(osv.osv):
     }
 
     def search(self, cr, user, args, offset=0, limit=None, order=None, context=None, count=False):
-        if not context: context = {}
+        if context is None: context = {}
         res = super(account_coda, self).search(cr, user, args=args, offset=offset, limit=limit, order=order,
                 context=context, count=count)
         if context.get('bank_statement', False) and not res:
diff --git a/addons/account_coda/wizard/account_coda_import.py b/addons/account_coda/wizard/account_coda_import.py
index 7db7faf0146..6219d210e53 100644
--- a/addons/account_coda/wizard/account_coda_import.py
+++ b/addons/account_coda/wizard/account_coda_import.py
@@ -66,7 +66,7 @@ class account_coda_import(osv.osv_memory):
         mod_obj = self.pool.get('ir.model.data')
         line_obj = self.pool.get('account.move.line')
 
-        if not context:
+        if context is None:
             context = {}
 
         data = self.read(cr, uid, ids)[0]
@@ -321,7 +321,7 @@ class account_coda_import(osv.osv_memory):
         }
 
     def action_open_window(self, cr, uid, data, context=None):
-        if not context:
+        if context is None:
             context = {}
 
         return {
diff --git a/addons/account_invoice_layout/account_invoice_layout.py b/addons/account_invoice_layout/account_invoice_layout.py
index 72504ad6ef7..5945eb88442 100644
--- a/addons/account_invoice_layout/account_invoice_layout.py
+++ b/addons/account_invoice_layout/account_invoice_layout.py
@@ -127,13 +127,13 @@ class account_invoice_line(osv.osv):
     def copy_data(self, cr, uid, id, default=None, context=None):
         if default is None:
             default = {}
-        if not context: context = {}
+        if context is None: context = {}
         default['state'] = self.browse(cr, uid, id, context=context).state
         return super(account_invoice_line, self).copy_data(cr, uid, id, default, context)
 
     def _fnct(self, cr, uid, ids, name, args, context=None):
         res = {}
-        if not context: context = {}
+        if context is None: context = {}
         lines = self.browse(cr, uid, ids, context=context)
         account_ids = [line.account_id.id for line in lines]
         account_names = dict(self.pool.get('account.account').name_get(cr, uid, account_ids, context=context))
@@ -181,7 +181,7 @@ account_invoice_line()
 class one2many_mod2(fields.one2many):
 
     def get(self, cr, obj, ids, name, user=None, offset=0, context=None, values=None):
-        if not context:
+        if context is None:
             context = {}
         if not values:
             values = {}
diff --git a/addons/account_payment/account_invoice.py b/addons/account_payment/account_invoice.py
index 11a1f7f2155..5876f138095 100644
--- a/addons/account_payment/account_invoice.py
+++ b/addons/account_payment/account_invoice.py
@@ -31,7 +31,7 @@ class Invoice(osv.osv):
         if not ids:
             return {}
         res = {}
-        if not context: context = {}
+        if context is None: context = {}
         for invoice in self.browse(cursor, user, ids, context=context):
             res[invoice.id] = 0.0
             if invoice.move_id:
diff --git a/addons/account_payment/account_move_line.py b/addons/account_payment/account_move_line.py
index 4f70d98a9cc..12e2b53bedb 100644
--- a/addons/account_payment/account_move_line.py
+++ b/addons/account_payment/account_move_line.py
@@ -50,7 +50,7 @@ class account_move_line(osv.osv):
     def _to_pay_search(self, cr, uid, obj, name, args, context=None):
         if not args:
             return []
-        if not context: context = {}
+        if context is None: context = {}
         line_obj = self.pool.get('account.move.line')
         query = line_obj._query_get(cr, uid, context={})
         where = ' and '.join(map(lambda x: '''(SELECT
@@ -89,7 +89,7 @@ class account_move_line(osv.osv):
         """
         payment_mode_obj = self.pool.get('payment.mode')
         line2bank = {}
-        if not context: context = {}
+        if context is None: context = {}
         if not ids:
             return {}
         bank_type = payment_mode_obj.suitable_bank_types(cr, uid, payment_type,
diff --git a/addons/account_payment/account_payment.py b/addons/account_payment/account_payment.py
index 0389902ad2a..10904e2d181 100644
--- a/addons/account_payment/account_payment.py
+++ b/addons/account_payment/account_payment.py
@@ -67,7 +67,7 @@ class payment_order(osv.osv):
         if not ids:
             return {}
         res = {}
-        if not context: context = {}
+        if context is None: context = {}
         for order in self.browse(cursor, user, ids, context=context):
             if order.line_ids:
                 res[order.id] = reduce(lambda x, y: x + y.amount, order.line_ids, 0.0)
@@ -128,7 +128,7 @@ class payment_order(osv.osv):
         return True
 
     def copy(self, cr, uid, id, default={}, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         default.update({
             'state': 'draft',
             'line_ids': [],
@@ -272,7 +272,7 @@ class payment_line(osv.osv):
     def _get_currency(self, cr, uid, context=None):
         user_obj = self.pool.get('res.users')
         currency_obj = self.pool.get('res.currency')
-        if not context: context = {}
+        if context is None: context = {}
         user = user_obj.browse(cr, uid, uid, context=context)
 
         if user.company_id:
@@ -410,7 +410,7 @@ class payment_line(osv.osv):
 
     def onchange_partner(self, cr, uid, ids, partner_id, payment_type, context=None):
         data = {}
-        if not context: context = {}
+        if context is None: context = {}
         partner_zip_obj = self.pool.get('res.partner.zip')
         partner_obj = self.pool.get('res.partner')
         payment_mode_obj = self.pool.get('payment.mode')
diff --git a/addons/account_sequence/account_sequence.py b/addons/account_sequence/account_sequence.py
index 25967b386d9..4c4058f0afd 100644
--- a/addons/account_sequence/account_sequence.py
+++ b/addons/account_sequence/account_sequence.py
@@ -30,7 +30,7 @@ class account_move(osv.osv):
     }
 
     def post(self, cr, uid, ids, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         obj_sequence = self.pool.get('ir.sequence')
         res = super(account_move, self).post(cr, uid, ids, context=context)
         seq_no = False
diff --git a/addons/account_voucher/account_voucher.py b/addons/account_voucher/account_voucher.py
index 37a7964298a..317d65eeaf4 100644
--- a/addons/account_voucher/account_voucher.py
+++ b/addons/account_voucher/account_voucher.py
@@ -32,7 +32,7 @@ class account_move_line(osv.osv):
 
     def _unreconciled(self, cr, uid, ids, prop, unknow_none, context=None):
         res = {}
-        if not context: context = {}
+        if context is None: context = {}
         for line in self.browse(cr, uid, ids, context=context):
             res[line.id] = line.debit - line.credit
             if line.reconcile_partial_id:
@@ -51,18 +51,18 @@ account_move_line()
 class account_voucher(osv.osv):
 
     def _get_type(self, cr, uid, ids, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         return context.get('type', False)
 
     def _get_period(self, cr, uid, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         if context.get('period_id', False):
             return context.get('period_id')
         periods = self.pool.get('account.period').find(cr, uid)
         return periods and periods[0] or False
 
     def _get_journal(self, cr, uid, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         journal_pool = self.pool.get('account.journal')
         if context.get('journal_id', False):
             return context.get('journal_id')
@@ -76,7 +76,7 @@ class account_voucher(osv.osv):
         return res and res[0] or False
 
     def _get_tax(self, cr, uid, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         journal_pool = self.pool.get('account.journal')
         journal_id = context.get('journal_id', False)
         if not journal_id:
@@ -96,7 +96,7 @@ class account_voucher(osv.osv):
         return False
 
     def _get_currency(self, cr, uid, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         journal_pool = self.pool.get('account.journal')
         journal_id = context.get('journal_id', False)
         if journal_id:
@@ -107,26 +107,26 @@ class account_voucher(osv.osv):
         return False
 
     def _get_partner(self, cr, uid, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         return context.get('partner_id', False)
 
     def _get_reference(self, cr, uid, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         return context.get('reference', False)
 
     def _get_narration(self, cr, uid, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         return context.get('narration', False)
 
     def name_get(self, cr, uid, ids, context=None):
         if not ids:
             return []
-        if not context: context = {}
+        if context is None: context = {}
         return [(r['id'], (str("%.2f" % r['amount']) or '')) for r in self.read(cr, uid, ids, ['amount'], context, load='_classic_write')]
 
     def fields_view_get(self, cr, uid, view_id=None, view_type=False, context=None, toolbar=False, submenu=False):
         mod_obj = self.pool.get('ir.model.data')
-        if not context: context = {}
+        if context is None: context = {}
         if not view_id and context.get('invoice_type', False):
             if context.get('invoice_type', False) in ('out_invoice', 'out_refund'):
                 result = mod_obj.get_object_reference(cr, uid, 'account_voucher', 'view_vendor_receipt_form')
@@ -224,7 +224,7 @@ class account_voucher(osv.osv):
         position_pool = self.pool.get('account.fiscal.position')
         voucher_line_pool = self.pool.get('account.voucher.line')
         voucher_pool = self.pool.get('account.voucher')
-        if not context: context = {}
+        if context is None: context = {}
 
         for voucher in voucher_pool.browse(cr, uid, ids, context=context):
             voucher_amount = 0.0
@@ -274,7 +274,7 @@ class account_voucher(osv.osv):
         }
         voucher_total = 0.0
         voucher_line_ids = []
-        if not context: context = {}
+        if context is None: context = {}
 
         total = 0.0
         total_tax = 0.0
@@ -333,7 +333,7 @@ class account_voucher(osv.osv):
         default = {
             'value':{},
         }
-        if not context: context = {}
+        if context is None: context = {}
 
         if not partner_id or not journal_id:
             return default
@@ -505,7 +505,7 @@ class account_voucher(osv.osv):
     def onchange_journal(self, cr, uid, ids, journal_id, line_ids, tax_id, partner_id, context=None):
         if not journal_id:
             return False
-        if not context: context = {}
+        if context is None: context = {}
         journal_pool = self.pool.get('account.journal')
         journal = journal_pool.browse(cr, uid, journal_id, context=context)
         account_id = journal.default_credit_account_id or journal.default_debit_account_id
@@ -535,7 +535,7 @@ class account_voucher(osv.osv):
     def cancel_voucher(self, cr, uid, ids, context=None):
         reconcile_pool = self.pool.get('account.move.reconcile')
         move_pool = self.pool.get('account.move')
-        if not context: context = {}
+        if context is None: context = {}
 
         for voucher in self.browse(cr, uid, ids, context=context):
             recs = []
@@ -591,7 +591,7 @@ class account_voucher(osv.osv):
                 terms = term_pool.compute(cr, uid, term_id, amount)
                 return terms
             return False
-        if not context:
+        if context is None:
             context = {}
         move_pool = self.pool.get('account.move')
         move_line_pool = self.pool.get('account.move.line')
@@ -769,7 +769,7 @@ class account_voucher_line(osv.osv):
     def _compute_balance(self, cr, uid, ids, name, args, context=None):
         currency_pool = self.pool.get('res.currency')
         rs_data = {}
-        if not context: context = {}
+        if context is None: context = {}
         for line in self.browse(cr, uid, ids, context=context):
             res = {}
             company_currency = line.voucher_id.journal_id.company_id.currency_id.id
@@ -821,7 +821,7 @@ class account_voucher_line(osv.osv):
         @return: Returns a dict which contains new values, and context
         """
         res = {}
-        if not context: context = {}
+        if context is None: context = {}
         move_line_pool = self.pool.get('account.move.line')
         if move_line_id:
             move_line = move_line_pool.browse(cr, user, move_line_id, context=context)
@@ -846,7 +846,7 @@ class account_voucher_line(osv.osv):
 
         @return: Returns a dict that contains default values for fields
         """
-        if not context: context = {}
+        if context is None: context = {}
         journal_id = context.get('journal_id', False)
         partner_id = context.get('partner_id', False)
         journal_pool = self.pool.get('account.journal')
@@ -883,7 +883,7 @@ class account_bank_statement(osv.osv):
 
     def button_cancel(self, cr, uid, ids, context=None):
         voucher_obj = self.pool.get('account.voucher')
-        if not context: context = {}
+        if context is None: context = {}
         for st in self.browse(cr, uid, ids, context=context):
             voucher_ids = []
             for line in st.line_ids:
@@ -897,7 +897,7 @@ class account_bank_statement(osv.osv):
         wf_service = netsvc.LocalService("workflow")
         move_line_obj = self.pool.get('account.move.line')
         bank_st_line_obj = self.pool.get('account.bank.statement.line')
-        if not context: context = {}
+        if context is None: context = {}
         st_line = bank_st_line_obj.browse(cr, uid, st_line_id, context=context)
         if st_line.voucher_id:
             voucher_obj.write(cr, uid, [st_line.voucher_id.id], {'number': next_number}, context=context)
@@ -923,7 +923,7 @@ class account_bank_statement_line(osv.osv):
             return {}
 
         res = {}
-        if not context: context = {}
+        if context is None: context = {}
 #        company_currency_id = False
         for line in self.browse(cursor, user, ids, context=context):
 #            if not company_currency_id:
@@ -945,7 +945,7 @@ class account_bank_statement_line(osv.osv):
     }
 
     def unlink(self, cr, uid, ids, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         voucher_obj = self.pool.get('account.voucher')
         statement_line = self.browse(cr, uid, ids, context=context)
         unlink_ids = []
diff --git a/addons/account_voucher/invoice.py b/addons/account_voucher/invoice.py
index 2cb31f15555..c8e90d283cc 100644
--- a/addons/account_voucher/invoice.py
+++ b/addons/account_voucher/invoice.py
@@ -27,7 +27,7 @@ class invoice(osv.osv):
 
     def invoice_pay_customer(self, cr, uid, ids, context=None):
         if not ids: return []
-        if not context: context = {}
+        if context is None: context = {}
         inv = self.browse(cr, uid, ids[0], context=context)
         return {
             'name':_("Pay Invoice"),
diff --git a/addons/account_voucher/wizard/account_statement_from_invoice.py b/addons/account_voucher/wizard/account_statement_from_invoice.py
index b85c95a58cc..df314012ccd 100644
--- a/addons/account_voucher/wizard/account_statement_from_invoice.py
+++ b/addons/account_voucher/wizard/account_statement_from_invoice.py
@@ -35,7 +35,7 @@ class account_statement_from_invoice_lines(osv.osv_memory):
     }
 
     def populate_statement(self, cr, uid, ids, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         statement_id = context.get('statement_id', False)
         if not statement_id:
             return {}
@@ -134,7 +134,7 @@ class account_statement_from_invoice(osv.osv_memory):
     }
 
     def search_invoices(self, cr, uid, ids, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         line_obj = self.pool.get('account.move.line')
         statement_obj = self.pool.get('account.bank.statement')
         journal_obj = self.pool.get('account.journal')
diff --git a/addons/analytic/analytic.py b/addons/analytic/analytic.py
index d1849f6da1e..d5be6c1a81d 100644
--- a/addons/analytic/analytic.py
+++ b/addons/analytic/analytic.py
@@ -29,7 +29,6 @@ class account_analytic_account(osv.osv):
     _description = 'Analytic Account'
 
     def _compute_level_tree(self, cr, uid, ids, child_ids, res, field_names, context=None):
-        if not context: context = {}
         def recursive_computation(account_id, res):
             account = self.browse(cr, uid, account_id)
             for son in account.child_ids:
@@ -93,7 +92,6 @@ class account_analytic_account(osv.osv):
         if not ids:
             return []
         res = []
-        if not context: context = {}
         for account in self.browse(cr, uid, ids, context=context):
             data = []
             acc = account
@@ -139,7 +137,6 @@ class account_analytic_account(osv.osv):
     }
 
     def _default_company(self, cr, uid, context=None):
-        if not context: context = {}
         user = self.pool.get('res.users').browse(cr, uid, uid, context=context)
         if user.company_id:
             return user.company_id.id
@@ -166,7 +163,6 @@ class account_analytic_account(osv.osv):
     def copy(self, cr, uid, id, default=None, context=None):
         if not default:
             default = {}
-        if not context: context = {}
         default['code'] = False
         default['line_ids'] = []
         return super(account_analytic_account, self).copy(cr, uid, id, default, context=context)
@@ -187,7 +183,7 @@ class account_analytic_account(osv.osv):
     def name_search(self, cr, uid, name, args=None, operator='ilike', context=None, limit=100):
         if not args:
             args=[]
-        if not context:
+        if context is None:
             context={}
         account = self.search(cr, uid, [('code', '=', name)]+args, limit=limit, context=context)
         if not account:
diff --git a/addons/auction/auction.py b/addons/auction/auction.py
index d4cad3bdc5a..019dcde8052 100644
--- a/addons/auction/auction.py
+++ b/addons/auction/auction.py
@@ -57,8 +57,6 @@ class auction_dates(osv.osv):
         return res
 
     def name_get(self, cr, uid, ids, context=None):
-        if not context:
-            context={}
         if not ids:
             return []
         reads = self.read(cr, uid, ids, ['name', 'auction1'], context)
@@ -68,8 +66,6 @@ class auction_dates(osv.osv):
     def _get_invoice(self, cr, uid, ids, name, arg, context=None):
         lots_obj = self.pool.get('auction.lots')
         result = {}
-        if not context:
-            context={}
         for data in self.browse(cr, uid, ids, context=context):
             buyer_inv_ids = []
             seller_inv_ids = []
@@ -122,8 +118,6 @@ class auction_dates(osv.osv):
 
         RETURN: True
         """
-        if not context:
-            context={}
         lots_obj = self.pool.get('auction.lots')
         lots_ids = lots_obj.search(cr, uid, [('auction_id', 'in', ids), ('state', '=', 'draft'), ('obj_price', '>', 0)])
         lots_obj.lots_invoice(cr, uid, lots_ids, {}, None)
@@ -196,8 +190,6 @@ class aie_category(osv.osv):
     }
 
     def name_get(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         res = []
         if not ids:
             return res
@@ -231,8 +223,6 @@ auction_lot_category()
 # Lots
 #----------------------------------------------------------
 def _type_get(self, cr, uid, context=None):
-    if not context:
-        context = {}
     obj = self.pool.get('auction.lot.category')
     ids = obj.search(cr, uid, [])
     res = obj.read(cr, uid, ids, ['name'], context)
@@ -247,23 +237,15 @@ class auction_lots(osv.osv):
     _description=__doc__
 
     def button_not_bought(self, cr, uid, ids, context=None):
-        if not context:
-            context={}
         return self.write(cr, uid, ids, {'state':'unsold'})
 
     def button_taken_away(self, cr, uid, ids, context=None):
-        if not context:
-            context={}
         return self.write(cr, uid, ids, {'state':'taken_away', 'ach_emp': True})
 
     def button_unpaid(self, cr, uid, ids, context=None):
-        if not context:
-            context={}
         return self.write(cr, uid, ids, {'state':'draft'})
 
     def button_bought(self, cr, uid, ids, context=None):
-        if not context:
-            context={}
         return self.write(cr, uid, ids, {'state':'sold'})
 
     def _getprice(self, cr, uid, ids, fields, args, context=None):
@@ -273,12 +255,10 @@ class auction_lots(osv.osv):
         @param context: A standard dictionary for contextual values
         @return: Dictionary of function fields value.
         """
-        if not context:
-            context = {}
 
         res = {}
         account_analytic_line_obj = self.pool.get('account.analytic.line')
-        lots = self.browse(cr, uid, ids, context)
+        lots = self.browse(cr, uid, ids, context=context)
         pt_tax = self.pool.get('account.tax')
         for lot in lots:
             taxes = []
@@ -364,8 +344,6 @@ class auction_lots(osv.osv):
         return res
 
     def onchange_obj_ret(self, cr, uid, ids, obj_ret, context=None):
-        if not context:
-            context={}
         if obj_ret:
             return {'value': {'obj_price': 0}}
         return {}
@@ -432,16 +410,12 @@ class auction_lots(osv.osv):
     }
 
     def name_get(self, cr, user, ids, context=None):
-        if not context:
-            context={}
         if not ids:
             return []
         result = [ (r['id'], str(r['obj_num'])+' - '+r['name']) for r in self.read(cr, user, ids, ['name', 'obj_num'])]
         return result
 
     def name_search(self, cr, user, name, args=None, operator='ilike', context=None):
-        if not context:
-            context={}
         if not args:
             args = []
         ids = []
@@ -585,14 +559,12 @@ class auction_lots(osv.osv):
 
     def buyer_proforma(self, cr, uid, ids, context=None):
 
-        if not context:
-            context={}
         invoices = {}
         inv_ref = self.pool.get('account.invoice')
         res_obj = self.pool.get('res.partner')
         inv_line_obj = self.pool.get('account.invoice.line')
         wf_service = netsvc.LocalService('workflow')
-        for lot in self.browse(cr, uid, ids, context):
+        for lot in self.browse(cr, uid, ids, context=context):
             if not lot.obj_price>0:
                 continue
             if not lot.ach_uid.id:
@@ -645,12 +617,10 @@ class auction_lots(osv.osv):
         """
         # use each list of object in turn
         invoices = {}
-        if not context:
-            context={}
         inv_ref=self.pool.get('account.invoice')
         inv_line_obj = self.pool.get('account.invoice.line')
         wf_service = netsvc.LocalService('workflow')
-        for lot in self.browse(cr, uid, ids, context):
+        for lot in self.browse(cr, uid, ids, context=context):
             if not lot.auction_id.id:
                 continue
             if lot.bord_vnd_id.id in invoices:
@@ -686,7 +656,7 @@ class auction_lots(osv.osv):
             }
             inv_line_obj.create(cr, uid, inv_line, context)
             inv_ref.button_compute(cr, uid, invoices.values())
-        for inv in inv_ref.browse(cr, uid, invoices.values(), context):
+        for inv in inv_ref.browse(cr, uid, invoices.values(), context=context):
             inv_ref.write(cr, uid, [inv.id], {
                 'check_total': inv.amount_total
             })
diff --git a/addons/auction/report/report_auction.py b/addons/auction/report/report_auction.py
index 25cdab88e89..406aedbed89 100644
--- a/addons/auction/report/report_auction.py
+++ b/addons/auction/report/report_auction.py
@@ -28,8 +28,6 @@ import time
 import tools
 
 def _type_get(self, cr, uid, context=None):
-    if not context:
-        context = {}
     obj = self.pool.get('auction.lot.category')
     ids = obj.search(cr, uid, [])
     res = obj.read(cr, uid, ids, ['name'], context)
diff --git a/addons/auction/wizard/auction_aie_send.py b/addons/auction/wizard/auction_aie_send.py
index ac04c80ce8c..1076f789b1d 100644
--- a/addons/auction/wizard/auction_aie_send.py
+++ b/addons/auction/wizard/auction_aie_send.py
@@ -60,7 +60,7 @@ class auction_lots_send_aie(osv.osv_memory):
          @param context: A standard dictionary 
          @return: A dictionary which of fields with values. 
         """
-        if not context: context = {}
+        if context is None: context = {}
         res = super(auction_lots_send_aie, self).default_get(cr, uid, fields, context=context)
         if 'uname' in fields and context.get('uname',False):
             res['uname'] = context.get('uname')
@@ -149,7 +149,7 @@ class auction_lots_send_aie(osv.osv_memory):
                 self._photo_bin_send(uname, passwd, ref, did, fname, bin)
     
     def get_dates(self, cr, uid, ids, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         import httplib
         data_obj = self.pool.get('ir.model.data')
         conn = httplib.HTTPConnection('www.auction-in-europe.com')
@@ -177,7 +177,6 @@ class auction_lots_send_aie(osv.osv_memory):
         }
     
     def _send(self, cr, uid, ids, context=None):
-        if not context: context = {}
         import pickle, thread, sql_db
         cr.execute('select name,aie_categ from auction_lot_category')
         vals = dict(cr.fetchall())
@@ -215,7 +214,6 @@ class auction_lots_send_aie(osv.osv_memory):
         return {}
     
     def send_pdf(self, cr, uid, ids, context=None):
-        if not context: context = {}
         threaded_calculation = threading.Thread(target=self._send, args=(cr, uid, ids, context))
         threaded_calculation.start()
         return {}
diff --git a/addons/auction/wizard/auction_aie_send_result.py b/addons/auction/wizard/auction_aie_send_result.py
index bf3d24c4aeb..dd302ac73b5 100644
--- a/addons/auction/wizard/auction_aie_send_result.py
+++ b/addons/auction/wizard/auction_aie_send_result.py
@@ -55,7 +55,7 @@ class auction_lots_pay(osv.osv_memory):
          @param context: A standard dictionary 
          @return: A dictionary which of fields with values. 
         """
-        if not context: context = {}
+        if context is None: context = {}
         res = super(auction_lots_pay, self).default_get(cr, uid, fields, context=context)
         if 'uname' in fields and context.get('uname',False):
             res['uname'] = context.get('uname')
@@ -98,7 +98,7 @@ class auction_lots_pay(osv.osv_memory):
         return post_multipart('auction-in-europe.com', "/bin/catalog_result.cgi", (('uname',uname),('password',passwd),('did',did)),(('file',catalog),))
     
     def get_dates(self, cr, uid, ids, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         import httplib
         conn = httplib.HTTPConnection('www.auction-in-europe.com')
         data_obj = self.pool.get('ir.model.data')
@@ -127,7 +127,7 @@ class auction_lots_pay(osv.osv_memory):
         }
     
     def send(self, cr, uid, ids, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         import pickle
         service = netsvc.LocalService("object_proxy")
         datas = self.read(cr, uid, ids[0],['uname','password','dates'])
diff --git a/addons/auction/wizard/auction_catalog_flagey_report.py b/addons/auction/wizard/auction_catalog_flagey_report.py
index 746de25b456..22c239e3d6c 100644
--- a/addons/auction/wizard/auction_catalog_flagey_report.py
+++ b/addons/auction/wizard/auction_catalog_flagey_report.py
@@ -36,7 +36,6 @@ class auction_catalog_flagey(osv.osv_memory):
          @param context: A standard dictionary 
          @return: A dictionary which of fields with values. 
         """
-        if not context: context = {}
         res = super(auction_catalog_flagey, self).default_get(cr, uid, fields, context=context)
         return res
     
@@ -53,7 +52,7 @@ class auction_catalog_flagey(osv.osv_memory):
         """
         lots_obj = self.pool.get('auction.lots')
         auc_dates_obj = self.pool.get('auction.dates')
-        if not context: context = {}
+        if context is None: context = {}
         current_auction = auc_dates_obj.browse(cr, uid, context.get('active_ids', []))
         v_lots = lots_obj.search(cr, uid, [('auction_id','=',current_auction.id)])
         v_ids = lots_obj.browse(cr, uid, v_lots, context=context)
@@ -72,7 +71,7 @@ class auction_catalog_flagey(osv.osv_memory):
          @param context: A standard dictionary 
          @return: Report  
         """
-        if not context: context = {}
+        if context is None: context = {}
         datas = {'ids': context.get('active_ids',[])}
         return {
             'type': 'ir.actions.report.xml',
diff --git a/addons/auction/wizard/auction_lots_able.py b/addons/auction/wizard/auction_lots_able.py
index 03004de41ce..d9da89385a1 100644
--- a/addons/auction/wizard/auction_lots_able.py
+++ b/addons/auction/wizard/auction_lots_able.py
@@ -38,7 +38,7 @@ class auction_lots_able(osv.osv_memory):
             @param uid: the current user’s ID for security checks,
             @param ids: List of auction lots able’s IDs.
         """
-        if not context: context = {}
+        if context is None: context = {}
         self.pool.get('auction.lots').write(cr, uid, context.get('active_ids', []), {'ach_emp':True})
         return {}
     
diff --git a/addons/auction/wizard/auction_lots_auction_move.py b/addons/auction/wizard/auction_lots_auction_move.py
index e77fe02528d..97330f922fe 100644
--- a/addons/auction/wizard/auction_lots_auction_move.py
+++ b/addons/auction/wizard/auction_lots_auction_move.py
@@ -44,7 +44,7 @@ class auction_lots_auction_move(osv.osv_memory):
         @param uid: the current user’s ID for security checks,
         @param ids: List of auction lots auction move’s IDs.
         """
-        if not context:
+        if context is None:
             context={}
         auction_bid_line_obj = self.pool.get('auction.bid_line')
         auction_lot_history_obj = self.pool.get('auction.lot.history')
diff --git a/addons/auction/wizard/auction_lots_buyer_map.py b/addons/auction/wizard/auction_lots_buyer_map.py
index 3e91bd635d1..f5e9d828936 100644
--- a/addons/auction/wizard/auction_lots_buyer_map.py
+++ b/addons/auction/wizard/auction_lots_buyer_map.py
@@ -42,7 +42,7 @@ class wiz_auc_lots_buyer_map(osv.osv_memory):
          @param context: A standard dictionary 
          @return: A dictionary which of fields with values. 
         """
-        if not context: context = {}
+        if context is None: context = {}
         res = super(wiz_auc_lots_buyer_map,self).default_get(cr, uid, fields, context=context)
         auction_lots_obj = self.pool.get('auction.lots')
         lots_ids = auction_lots_obj.search(cr, uid, [('ach_uid', '=', ''), ('ach_login', '!=', '')])
@@ -63,8 +63,6 @@ class wiz_auc_lots_buyer_map(osv.osv_memory):
          @param context: A standard dictionary 
          @return: login field from current record. 
         """
-        if not context:
-            context={}
         lots_obj = self.pool.get('auction.lots')
         for rec in lots_obj.browse(cr, uid, ids, context=context):
             if (len(ids)==1) and (not rec.ach_uid and not rec.ach_login):
@@ -82,7 +80,7 @@ class wiz_auc_lots_buyer_map(osv.osv_memory):
          @param ids: List of ids 
          @param context: A standard dictionary 
         """
-        if not context:
+        if context is None:
             context={}
         rec_ids = context and context.get('active_ids',[]) or []
         assert rec_ids, _('Active IDs not Found')
@@ -103,7 +101,7 @@ class wiz_auc_lots_buyer_map(osv.osv_memory):
          @param context: A standard dictionary 
          @return: New arch of view.
         """
-        if not context:
+        if context is None:
             context={}
         record_ids = context and context.get('active_ids', []) or []
         res = super(wiz_auc_lots_buyer_map, self).fields_view_get(cr, uid, view_id=view_id, view_type=view_type, context=context, toolbar=toolbar,submenu=False)
diff --git a/addons/auction/wizard/auction_lots_cancel.py b/addons/auction/wizard/auction_lots_cancel.py
index b731f0e4c51..62313315bd9 100644
--- a/addons/auction/wizard/auction_lots_cancel.py
+++ b/addons/auction/wizard/auction_lots_cancel.py
@@ -40,7 +40,7 @@ class auction_lots_cancel(osv.osv):
             @param context: A standard dictionary
             @return:
             """
-            if not context:
+            if context is None:
                 context={}
             lots_obj = self.pool.get('auction.lots')
             invoice_obj = self.pool.get('account.invoice')
diff --git a/addons/auction/wizard/auction_lots_enable.py b/addons/auction/wizard/auction_lots_enable.py
index a7f8c43a778..41b6ec909cc 100644
--- a/addons/auction/wizard/auction_lots_enable.py
+++ b/addons/auction/wizard/auction_lots_enable.py
@@ -35,7 +35,7 @@ class auction_lots_enable(osv.osv_memory):
         @param uid: the current user’s ID for security checks,
         @param ids: List of auction lots enable’s IDs.
         """
-        if not context: context = {}
+        if context is None: context = {}
         self.pool.get('auction.lots').write(cr, uid, context.get('active_id',False), {'ach_emp':False})
         return {}
     
diff --git a/addons/auction/wizard/auction_lots_invoice.py b/addons/auction/wizard/auction_lots_invoice.py
index eac3d397bc1..ac296ec1dd7 100644
--- a/addons/auction/wizard/auction_lots_invoice.py
+++ b/addons/auction/wizard/auction_lots_invoice.py
@@ -46,7 +46,7 @@ class auction_lots_invoice(osv.osv_memory):
          @param context: A standard dictionary
          @return: A dictionary which of fields with values.
         """
-        if not context: context = {}
+        if context is None: context = {}
         res = super(auction_lots_invoice, self).default_get(cr, uid, fields, context=context)
         service = netsvc.LocalService("object_proxy")
         lots = service.execute(cr.dbname, uid, 'auction.lots', 'read', context.get('active_ids', []))
@@ -102,7 +102,7 @@ class auction_lots_invoice(osv.osv_memory):
         @param ids: List of Auction lots make invoice buyer’s IDs
         @return: dictionary of  account invoice form.
         """
-        if not context: context = {}
+        if context is None: context = {}
         service = netsvc.LocalService("object_proxy")
         datas = {'ids' : context.get('active_ids',[])}
         res = self.read(cr, uid, ids, ['number','ach_uid'])
diff --git a/addons/auction/wizard/auction_lots_make_invoice.py b/addons/auction/wizard/auction_lots_make_invoice.py
index e4a6f1dd924..3a87a202b74 100644
--- a/addons/auction/wizard/auction_lots_make_invoice.py
+++ b/addons/auction/wizard/auction_lots_make_invoice.py
@@ -50,7 +50,7 @@ class auction_lots_make_invoice(osv.osv_memory):
         @param context: A standard dictionary 
         @return: A dictionary which of fields with values. 
         """        
-        if not context:
+        if context is None:
             context={}
         res = super(auction_lots_make_invoice, self).default_get(cr, uid, fields, context=context)
         lots_obj = self.pool.get('auction.lots') 
@@ -69,7 +69,7 @@ class auction_lots_make_invoice(osv.osv_memory):
         @param ids: List of Auction lots make invoice’s IDs
         @return: dictionary of  account invoice form.
         """
-        if not context:
+        if context is None:
             context={}
         order_obj = self.pool.get('auction.lots')
         mod_obj = self.pool.get('ir.model.data') 
diff --git a/addons/auction/wizard/auction_lots_make_invoice_buyer.py b/addons/auction/wizard/auction_lots_make_invoice_buyer.py
index 5732da610d8..dc39ccbb717 100644
--- a/addons/auction/wizard/auction_lots_make_invoice_buyer.py
+++ b/addons/auction/wizard/auction_lots_make_invoice_buyer.py
@@ -45,7 +45,7 @@ class auction_lots_make_invoice_buyer(osv.osv_memory):
          @param context: A standard dictionary 
          @return: A dictionary which of fields with values. 
         """        
-        if not context:
+        if context is None:
             context={}
         res = super(auction_lots_make_invoice_buyer, self).default_get(cr, uid, fields, context=context)
         lots_obj=self.pool.get('auction.lots')
diff --git a/addons/auction/wizard/auction_lots_numerotate.py b/addons/auction/wizard/auction_lots_numerotate.py
index 260f9c6bf00..a4532059d3d 100644
--- a/addons/auction/wizard/auction_lots_numerotate.py
+++ b/addons/auction/wizard/auction_lots_numerotate.py
@@ -48,7 +48,7 @@ class auction_lots_numerotate_per_lot(osv.osv_memory):
          @param context: A standard dictionary 
          @return: A dictionary which of fields with values. 
         """
-        if not context: context = {}
+        if context is None: context = {}
         res = super(auction_lots_numerotate_per_lot, self).default_get(cr, uid, fields, context=context)
         active_id = context.get('active_id',False)
         active_model = context.get('active_model')
@@ -91,6 +91,7 @@ class auction_lots_numerotate_per_lot(osv.osv_memory):
         }
     
     def numerotate(self, cr, uid, ids, context=None):
+        if context is None: context = {}
         record_ids = context and context.get('active_ids',False) or False
         assert record_ids, _('Active IDs not Found')
         datas = self.read(cr, uid, ids[0], ['bord_vnd_id','lot_num','obj_num'])
@@ -133,6 +134,7 @@ class auction_lots_numerotate_per_lot(osv.osv_memory):
         return lots_datas[0]
     
     def test_exist(self, cr, uid, ids, context=None):
+        if context is None: context = {}
         record_ids = context and context.get('active_ids',False) or False
         assert record_ids, _('Active IDs not Found')
         data_obj = self.pool.get('ir.model.data')
diff --git a/addons/auction/wizard/auction_lots_sms_send.py b/addons/auction/wizard/auction_lots_sms_send.py
index d2f1b217951..ea1d094f55b 100644
--- a/addons/auction/wizard/auction_lots_sms_send.py
+++ b/addons/auction/wizard/auction_lots_sms_send.py
@@ -44,7 +44,7 @@ class auction_lots_sms_send(osv.osv_memory):
             @param context: A standard dictionary 
             @return: number indicating the acknowledgement
         """
-        if not context: context = {}
+        if context is None: context = {}
         lot_obj = self.pool.get('auction.lots')
         partner_obj = self.pool.get('res.partner')
         partner_address_obj = self.pool.get('res.partner.address')
diff --git a/addons/auction/wizard/auction_pay_buy.py b/addons/auction/wizard/auction_pay_buy.py
index ce3ee20a339..1dc029ed12a 100644
--- a/addons/auction/wizard/auction_pay_buy.py
+++ b/addons/auction/wizard/auction_pay_buy.py
@@ -48,7 +48,7 @@ class auction_pay_buy(osv.osv_memory):
          @param context: A standard dictionary 
          @return: A dictionary which of fields with values. 
         """        
-        if not context:
+        if context is None:
             context={}
         res = super(auction_pay_buy, self).default_get(cr, uid, fields, context=context)
         auction_lots_obj= self.pool.get('auction.lots')       
@@ -70,7 +70,7 @@ class auction_pay_buy(osv.osv_memory):
         @param context: A standard dictionary 
         @return: 
         """        
-        if not context: context = {}
+        if context is None: context = {}
         lot_obj = self.pool.get('auction.lots')
         bank_statement_line_obj = self.pool.get('account.bank.statement.line')
         
diff --git a/addons/auction/wizard/auction_pay_sel.py b/addons/auction/wizard/auction_pay_sel.py
index e3dd5402b61..23b16743246 100644
--- a/addons/auction/wizard/auction_pay_sel.py
+++ b/addons/auction/wizard/auction_pay_sel.py
@@ -42,7 +42,7 @@ class auction_pay_sel(osv.osv_memory):
         @param context: A standard dictionary
         @return:
         """
-        if not context: context = {}
+        if context is None: context = {}
         lot = self.pool.get('auction.lots').browse(cr, uid, context['active_id'], context=context)
         invoice_obj = self.pool.get('account.invoice')
         for datas in self.read(cr, uid, ids, context=context):
diff --git a/addons/auction/wizard/auction_payer_sel.py b/addons/auction/wizard/auction_payer_sel.py
index b6dec9546d3..f1df4d1cd47 100644
--- a/addons/auction/wizard/auction_payer_sel.py
+++ b/addons/auction/wizard/auction_payer_sel.py
@@ -26,7 +26,7 @@ class auction_payer(osv.osv_memory):
     _description = "Auction payer"
     
     def payer(self, cr, uid, ids, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         self.pool.get('auction.lots').write(cr, uid, context.get('active_ids', []), {'is_ok':True, 'state':'paid'})
         return {}
     
@@ -46,7 +46,7 @@ class auction_payer_sel(osv.osv_memory):
         @param uid: the current user’s ID for security checks,
         @param ids: List of auction payer sel’s IDs.
         """
-        if not context: context = {}
+        if context is None: context = {}
         self.pool.get('auction.lots').write(cr, uid, context.get('active_ids', []), {'paid_vnd':True})
         return {}
     
diff --git a/addons/auction/wizard/auction_taken.py b/addons/auction/wizard/auction_taken.py
index 4ad4fcbe372..8ada436ae5d 100644
--- a/addons/auction/wizard/auction_taken.py
+++ b/addons/auction/wizard/auction_taken.py
@@ -42,7 +42,7 @@ class auction_taken(osv.osv_memory):
           @param ids: List of Auction taken’s IDs
           @return: dictionary of lot_ids fields with empty list 
           """
-          if not context:
+          if context is None:
               context={}
           lot_obj = self.pool.get('auction.lots')
           for current in self.browse(cr, uid, ids, context=context):
diff --git a/addons/auction/wizard/auction_transfer_unsold_object.py b/addons/auction/wizard/auction_transfer_unsold_object.py
index 65b4329f622..8bc0cb8cb5b 100644
--- a/addons/auction/wizard/auction_transfer_unsold_object.py
+++ b/addons/auction/wizard/auction_transfer_unsold_object.py
@@ -63,7 +63,7 @@ class auction_transfer_unsold_object(osv.osv):
             @param context: A standard dictionary 
             @return: 
             """
-            if not context: context = {}
+            if context is None: context = {}
             bid_line_obj = self.pool.get('auction.bid_line')
             lots_obj = self.pool.get('auction.lots')
             lot_history_obj = self.pool.get('auction.lot.history')
diff --git a/addons/audittrail/audittrail.py b/addons/audittrail/audittrail.py
index c2ef5f5d4a4..d394eab6563 100644
--- a/addons/audittrail/audittrail.py
+++ b/addons/audittrail/audittrail.py
@@ -196,8 +196,6 @@ class audittrail_objects_proxy(osv_pool):
         @param values: Values for field to be converted into textual values
         @return: values: List of textual values for given fields
         """
-        if not context:
-            context = {}
         pool = pooler.get_pool(cr.dbname)
         field_pool = pool.get('ir.model.fields')
         model_pool = pool.get('ir.model')
diff --git a/addons/audittrail/wizard/audittrail_view_log.py b/addons/audittrail/wizard/audittrail_view_log.py
index 54955dbc388..7d3894c8a1d 100644
--- a/addons/audittrail/wizard/audittrail_view_log.py
+++ b/addons/audittrail/wizard/audittrail_view_log.py
@@ -42,8 +42,6 @@ class audittrail_view_log(osv.osv_memory):
         @param ids: List of audittrail view log’s IDs.
         @return: Dictionary of  audittrail log form on given date range.
         """
-        if not context:
-            context = {}
 
         mod_obj = self.pool.get('ir.model.data')
         act_obj = self.pool.get('ir.actions.act_window')
diff --git a/addons/base_action_rule/base_action_rule.py b/addons/base_action_rule/base_action_rule.py
index 43bed5f5ecd..bf34c137b5a 100644
--- a/addons/base_action_rule/base_action_rule.py
+++ b/addons/base_action_rule/base_action_rule.py
@@ -157,7 +157,7 @@ the rule to mark CC(mail to any other person defined in actions)."),
         return True
 
     def _create(self, old_create, model, context=None):
-        if not context:
+        if context is None:
             context  = {}
         def make_call_old(cr, uid, vals, context=context):
             new_id = old_create(cr, uid, vals, context=context)
@@ -167,7 +167,7 @@ the rule to mark CC(mail to any other person defined in actions)."),
         return make_call_old
     
     def _write(self, old_write, model, context=None):
-        if not context:
+        if context is None:
             context  = {}
         def make_call_old(cr, uid, ids, vals, context=context):
             if isinstance(ids, (str, int, long)):
@@ -178,7 +178,7 @@ the rule to mark CC(mail to any other person defined in actions)."),
         return make_call_old
 
     def _register_hook(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         for action_rule in self.browse(cr, uid, ids, context=context):
             model = action_rule.model_id.model
diff --git a/addons/base_calendar/base_calendar.py b/addons/base_calendar/base_calendar.py
index 9aa5b4bfd9e..2228a33c2e2 100644
--- a/addons/base_calendar/base_calendar.py
+++ b/addons/base_calendar/base_calendar.py
@@ -106,7 +106,6 @@ def _links_get(self, cr, uid, context=None):
     @param context: A standard dictionary for contextual values
     @return: list of dictionary which contain object and name and id.
     """
-    if not context: context = {}
     obj = self.pool.get('res.request.link')
     ids = obj.search(cr, uid, [])
     res = obj.read(cr, uid, ids, ['object', 'name'], context=context)
@@ -234,7 +233,6 @@ class calendar_attendee(osv.osv):
         """
         name = name[0]
         result = {}
-        if not context: context = {}
         for attdata in self.browse(cr, uid, ids, context=context):
             id = attdata.id
             result[id] = {}
@@ -301,7 +299,6 @@ class calendar_attendee(osv.osv):
         @param context: A standard dictionary for contextual values
         @return: list of dictionary which contain object and name and id.
         """
-        if not context: context = {}
         obj = self.pool.get('res.request.link')
         ids = obj.search(cr, uid, [])
         res = obj.read(cr, uid, ids, ['object', 'name'], context=context)
@@ -315,7 +312,6 @@ class calendar_attendee(osv.osv):
         @param context: A standard dictionary for contextual values
         @return: list of dictionary which contain code and name and id.
         """
-        if not context: context = {}
         obj = self.pool.get('res.lang')
         ids = obj.search(cr, uid, [])
         res = obj.read(cr, uid, ids, ['code', 'name'], context=context)
@@ -1595,7 +1591,6 @@ true, it will allow you to hide the event alarm information without removing it.
         @return: True
         """
         res = False
-        if not context: context = {}
         for event_datas in self.read(cr, uid, ids, ['date', 'rrule', 'exdate'], context=context):
             event_id = event_datas['id']
             if isinstance(event_id, (int, long)):
@@ -1700,7 +1695,6 @@ class calendar_todo(osv.osv):
         """
 
         res = {}
-        if not context: context = {}
         for event in self.browse(cr, uid, ids, context=context):
             res[event.id] = event.date_start
         return res
diff --git a/addons/base_calendar/wizard/base_calendar_invite_attendee.py b/addons/base_calendar/wizard/base_calendar_invite_attendee.py
index af3e5ef3703..48f39e609f9 100644
--- a/addons/base_calendar/wizard/base_calendar_invite_attendee.py
+++ b/addons/base_calendar/wizard/base_calendar_invite_attendee.py
@@ -62,7 +62,7 @@ send an Email to Invited Person')
         @return: Dictionary of {}.
         """
 
-        if not context:
+        if context is None:
             context = {}
 
         model = False
diff --git a/addons/base_calendar/wizard/base_calendar_set_exrule.py b/addons/base_calendar/wizard/base_calendar_set_exrule.py
index 44b70b03ee2..fa65c27f72c 100644
--- a/addons/base_calendar/wizard/base_calendar_set_exrule.py
+++ b/addons/base_calendar/wizard/base_calendar_set_exrule.py
@@ -82,7 +82,7 @@ class base_calendar_set_exrule(osv.osv_memory):
         @param fields: List of fields for default value
         @param context: A standard dictionary for contextual values
         """
-        if not context: context = {}
+        if context is None: context = {}
         event_obj = self.pool.get(context.get('active_model'))
         for event in event_obj.browse(cr, uid, context.get('active_ids', []), context=context):
             if not event.rrule:
@@ -103,7 +103,7 @@ class base_calendar_set_exrule(osv.osv_memory):
         weekstring = ''
         monthstring = ''
         yearstring = ''
-        if not context: context = {}
+        if context is None: context = {}
         ex_id = base_calendar.base_calendar_id2real_id(context.get('active_id', False))
         model = context.get('model', False)
         model_obj = self.pool.get(model)
diff --git a/addons/base_calendar/wizard/calendar_event_edit_all.py b/addons/base_calendar/wizard/calendar_event_edit_all.py
index e9698a33445..a9b0a9f347e 100644
--- a/addons/base_calendar/wizard/calendar_event_edit_all.py
+++ b/addons/base_calendar/wizard/calendar_event_edit_all.py
@@ -69,7 +69,7 @@ class calendar_event_edit_all(osv.osv_memory):
         @param ids: List of calendar event edit all’s IDs
         @return: dictionary {}
         """
-        if not context:
+        if context is None:
             context = {}
 
         context_id = context and context.get('active_id', False) or False
diff --git a/addons/base_contact/base_contact.py b/addons/base_contact/base_contact.py
index d0339f55d7a..827ac56fa17 100644
--- a/addons/base_contact/base_contact.py
+++ b/addons/base_contact/base_contact.py
@@ -36,7 +36,6 @@ class res_partner_contact(osv.osv):
             @fields: Get Fields
             @param context: A standard dictionary for contextual values
             @param arg: list of tuples of form [(‘name_of_the_field’, ‘operator’, value), ...]. """
-        if not context: context = {}
         res = dict.fromkeys(ids, False)
 
         res_partner_job_obj = self.pool.get('res.partner.job')
@@ -92,7 +91,6 @@ class res_partner_contact(osv.osv):
         if not len(ids):
             return []
         res = []
-        if not context: context = {}
         for contact in self.browse(cr, user, ids, context=context):
             _contact = ""
             if contact.title:
@@ -133,7 +131,7 @@ class res_partner_address(osv.osv):
         if not len(ids):
             return []
         res = []
-        if not context: context = {}
+        if context is None: context = {}
         for r in self.read(cr, user, ids, ['zip', 'city', 'partner_id', 'street']):
             if context.get('contact_display', 'contact')=='partner' and r['partner_id']:
                 res.append((r['id'], r['partner_id'][1]))
@@ -238,7 +236,6 @@ class res_partner_job(osv.osv):
             @address_id : ID of the Address selected,
             @param context: A standard dictionary for contextual values
         """
-        if not context: context = {}
         partner_id = False
         if address_id:
             address = self.pool.get('res.partner.address')\
diff --git a/addons/base_contact/base_contact_installer.py b/addons/base_contact/base_contact_installer.py
index a20e04849c3..6d979da7a02 100644
--- a/addons/base_contact/base_contact_installer.py
+++ b/addons/base_contact/base_contact_installer.py
@@ -35,7 +35,6 @@ class base_contact_installer(osv.osv_memory):
         """
         This function is used to create contact and address from existing partner address
         """
-        if not context: context = {}
         obj = self.pool.get("base.contact.installer").browse(cr, uid, uid, context=context)
         if obj.migrate:
             cr.execute("""DROP TRIGGER  IF EXISTS contactjob on res_partner_contact;
diff --git a/addons/base_iban/base_iban.py b/addons/base_iban/base_iban.py
index 345c0b8a797..e6c61d69836 100644
--- a/addons/base_iban/base_iban.py
+++ b/addons/base_iban/base_iban.py
@@ -75,14 +75,12 @@ class res_partner_bank(osv.osv):
 
     def create(self, cr, uid, vals, context=None):
         #overwrite to format the iban number correctly
-        if not context: context = {}
         if 'iban' in vals and vals['iban']:
             vals['iban'] = _format_iban(vals['iban'])
         return super(res_partner_bank, self).create(cr, uid, vals, context)
 
     def write(self, cr, uid, ids, vals, context=None):
         #overwrite to format the iban number correctly
-        if not context: context = {}
         if 'iban' in vals and vals['iban']:
             vals['iban'] = _format_iban(vals['iban'])
         return super(res_partner_bank, self).write(cr, uid, ids, vals, context)
@@ -91,7 +89,6 @@ class res_partner_bank(osv.osv):
         '''
         Check the IBAN number
         '''
-        if not context: context = {}
         for bank_acc in self.browse(cr, uid, ids, context=context):
             if not bank_acc.iban:
                 continue
@@ -126,7 +123,6 @@ class res_partner_bank(osv.osv):
     def name_get(self, cr, uid, ids, context=None):
         res = []
         to_check_ids = []
-        if not context: context = {}
         for id in self.browse(cr, uid, ids, context=context):
             if id.state=='iban':
                 res.append((id.id,id.iban))
@@ -137,7 +133,6 @@ class res_partner_bank(osv.osv):
 
     def search(self, cr, uid, args, offset=0, limit=None, order=None, context=None, count=False):
     #overwrite the search method in order to search not only on bank type == basic account number but also on type == iban
-        if not context: context = {}
         res = super(res_partner_bank,self).search(cr, uid, args, offset, limit, order, context=context, count=count)
         if filter(lambda x:x[0]=='acc_number' ,args):
             #get the value of the search
@@ -156,7 +151,6 @@ class res_partner_bank(osv.osv):
         This function returns the bank account number computed from the iban account number, thanks to the mapping_list dictionary that contains the rules associated to its country.
         '''
         res = {}
-        if not context: context = {}
         mapping_list = {
          #TODO add rules for others countries
             'be': lambda x: x[4:],
diff --git a/addons/base_module_doc_rst/base_module_doc_rst.py b/addons/base_module_doc_rst/base_module_doc_rst.py
index 18036edf09e..57b26fd0d44 100755
--- a/addons/base_module_doc_rst/base_module_doc_rst.py
+++ b/addons/base_module_doc_rst/base_module_doc_rst.py
@@ -37,7 +37,6 @@ class module(osv.osv):
 
     def _get_graphical_representation(self, cr, uid, model_ids, level=1, context=None):
         obj_model = self.pool.get('ir.model')
-        if not context: context = {}
         if level == 0:
             return tuple()
         relation = []
@@ -100,7 +99,7 @@ class module(osv.osv):
         return obj_ids
 
     def get_relation_graph(self, cr, uid, module_name, context=None):
-        if not context: context = {}
+        if context is None: context = {}
         object_ids = self._get_module_objects(cr, uid, module_name, context=context)
         if not object_ids:
             return {'module_file': False}
diff --git a/addons/base_module_doc_rst/wizard/generate_relation_graph.py b/addons/base_module_doc_rst/wizard/generate_relation_graph.py
index a70c8eaa0f7..7b04f183129 100644
--- a/addons/base_module_doc_rst/wizard/generate_relation_graph.py
+++ b/addons/base_module_doc_rst/wizard/generate_relation_graph.py
@@ -30,7 +30,6 @@ form_rep = '''<?xml version="1.0"?>
 
 def _get_graph(self, cr, uid, datas, context=None):
     mod_obj = pooler.get_pool(cr.dbname).get('ir.module.module')
-    if not context: context = {}
     modules = mod_obj.browse(cr, uid, datas['ids'], context=context)
     for module in modules:
         module_data = mod_obj.get_relation_graph(cr, uid, module.name, context=context)
diff --git a/addons/base_report_creator/base_report_creator.py b/addons/base_report_creator/base_report_creator.py
index 13447778043..24a721debe6 100644
--- a/addons/base_report_creator/base_report_creator.py
+++ b/addons/base_report_creator/base_report_creator.py
@@ -363,7 +363,6 @@ class report_creator(osv.osv):
         @return: Dictionary of sql query.
         """
         result = {}
-        if not context: context = {}
         for obj in self.browse(cr, uid, ids, context=context):
             fields = []
             groupby = []
@@ -452,7 +451,7 @@ class report_creator(osv.osv):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for base creator report form
         """
-        if not context:
+        if context is None:
             context = {}
 
         rep = self.browse(cr, uid, ids, context=context)
@@ -487,7 +486,6 @@ class report_creator(osv.osv):
         @return: True if display field which are  stored in database.
                      or false if display field which are not store in dtabase.
         """
-        if not context: context = {}
         this_objs = self.browse(cr, uid, ids, context=context)
         for obj in this_objs:
             for fld in obj.field_ids:
@@ -509,7 +507,6 @@ class report_creator(osv.osv):
         @return: True if model colume type is in integer or float.
                      or false model colume type is not in integer or float.
         """
-        if not context: context = {}
         aggregate_columns = ('integer', 'float')
         apply_functions = ('sum', 'min', 'max', 'avg', 'count')
         this_objs = self.browse(cr, uid, ids, context=context)
@@ -525,7 +522,6 @@ class report_creator(osv.osv):
 
     def _calander_view_error(self, cr, uid, ids, context=None):
         required_types = []
-        if not context: context = {}
         this_objs = self.browse(cr, uid, ids, context=context)
         for obj in this_objs:
             if obj.view_type1 == 'calendar' or obj.view_type2 == 'calendar' or obj.view_type3 == 'calendar':
diff --git a/addons/base_report_creator/wizard/report_menu_create.py b/addons/base_report_creator/wizard/report_menu_create.py
index 84b952f976a..9f6eba3f806 100644
--- a/addons/base_report_creator/wizard/report_menu_create.py
+++ b/addons/base_report_creator/wizard/report_menu_create.py
@@ -40,7 +40,7 @@ class report_menu_create(osv.osv_memory):
         @param ids: List of Report Menu Create's IDs
         @return: Dictionary {}.
         """
-        if not context:
+        if context is None:
             context = {}
         context_id = context and context.get('active_id', False) or False
         obj_menu = self.pool.get('ir.ui.menu')
diff --git a/addons/base_report_designer/base_report_designer.py b/addons/base_report_designer/base_report_designer.py
index 93c05a93f48..16edc45560d 100644
--- a/addons/base_report_designer/base_report_designer.py
+++ b/addons/base_report_designer/base_report_designer.py
@@ -46,7 +46,6 @@ class report_xml(osv.osv):
         '''
         Untested function
         '''
-        if not context: context = {}
         pool = pooler.get_pool(cr.dbname)
         sxwval = StringIO(base64.decodestring(file_sxw))
         if file_type=='sxw':
@@ -61,7 +60,6 @@ class report_xml(osv.osv):
         return True
 
     def report_get(self, cr, uid, report_id, context=None):
-        if not context: context = {}
         report = self.browse(cr, uid, report_id, context=context)
         return {
             'file_type' : report.report_type, 
diff --git a/addons/base_report_designer/installer.py b/addons/base_report_designer/installer.py
index 68947ef6d88..d21fd11af00 100644
--- a/addons/base_report_designer/installer.py
+++ b/addons/base_report_designer/installer.py
@@ -30,7 +30,6 @@ class base_report_designer_installer(osv.osv_memory):
     _inherit = 'res.config.installer'
 
     def default_get(self, cr, uid, fields, context=None):
-        if not context: context = {}
         data = super(base_report_designer_installer, self).default_get(cr, uid, fields, context=context)
         plugin_file = open(addons.get_module_resource('base_report_designer','plugin', 'openerp_report_designer.zip'),'rb')
         data['plugin_file'] = base64.encodestring(plugin_file.read())
diff --git a/addons/base_report_designer/wizard/base_report_designer_modify.py b/addons/base_report_designer/wizard/base_report_designer_modify.py
index e96f6ced73f..fef2d1c56af 100644
--- a/addons/base_report_designer/wizard/base_report_designer_modify.py
+++ b/addons/base_report_designer/wizard/base_report_designer_modify.py
@@ -39,7 +39,6 @@ class base_report_sxw(osv.osv_memory):
 
 
     def get_report(self, cr, uid, ids, context=None):
-        if not context: context = {}
         data = self.read(cr,uid,ids)[0]
         data_obj = self.pool.get('ir.model.data')
         id2 = data_obj._get_id(cr, uid, 'base_report_designer', 'view_base_report_file_sxw')
@@ -75,12 +74,11 @@ class base_report_file_sxw(osv.osv_memory):
              @return: A dictionary which of fields with values.
 
         """
-        if not context: context = {}
         res = super(base_report_file_sxw, self).default_get(cr, uid, fields, context=context)
         report_id1 = self.pool.get('base.report.sxw').search(cr,uid,[])
         data=self.pool.get('base.report.sxw').read(cr,uid,report_id1)[0]
         report = self.pool.get('ir.actions.report.xml').browse(cr, uid, data['report_id'], context=context)
-        if not context:
+        if context is None:
             context={}
         if 'report_id' in fields:
             res['report_id'] = data['report_id']
@@ -96,7 +94,6 @@ class base_report_file_sxw(osv.osv_memory):
     def upload_report(self, cr, uid, ids, context=None):
         from base_report_designer import  openerp_sxw2rml
         import StringIO
-        if not context: context = {}
         data=self.read(cr,uid,ids)[0]
         sxwval = StringIO.StringIO(base64.decodestring(data['file_sxw_upload']))
         fp = tools.file_open('normalized_oo2rml.xsl',subdir='addons/base_report_designer/openerp_sxw2rml')
@@ -137,8 +134,6 @@ class base_report_rml_save(osv.osv_memory):
              @return: A dictionary which of fields with values.
 
         """
-        if not context:
-            context = {}
         
         res = super(base_report_rml_save, self).default_get(cr, uid, fields, context=context)
         report_id = self.pool.get('base.report.sxw').search(cr,uid,[])
diff --git a/addons/base_synchro/wizard/base_synchro.py b/addons/base_synchro/wizard/base_synchro.py
index 7c6ab6e42f0..d3c1de40d6d 100644
--- a/addons/base_synchro/wizard/base_synchro.py
+++ b/addons/base_synchro/wizard/base_synchro.py
@@ -66,8 +66,6 @@ class base_synchro(osv.osv_memory):
     report_write = 0
 
     def synchronize(self, cr, uid, server, object, context=None):
-        if not context:
-            context = {}
         pool = pooler.get_pool(cr.dbname)
         self.meta = {}
         ids = []
@@ -139,8 +137,6 @@ class base_synchro(osv.osv_memory):
         return True
 
     def get_id(self, cr, uid, object_id, id, action, context=None):
-        if not context:
-            context = {}
         pool = pooler.get_pool(cr.dbname)
         line_pool = pool.get('base.synchro.obj.line')
         field_src = (action=='u') and 'local_id' or 'remote_id'
@@ -154,8 +150,6 @@ class base_synchro(osv.osv_memory):
     def relation_transform(self, cr, uid, pool_src, pool_dest, object, id, action, context=None):
         if not id:
             return False
-        if not context:
-            context = {}
         pool = pooler.get_pool(cr.dbname)
         cr.execute('''select o.id from base_synchro_obj o left join ir_model m on (o.model_id =m.id) where
                 m.model=%s and
@@ -189,8 +183,6 @@ class base_synchro(osv.osv_memory):
 
     def data_transform(self, cr, uid, pool_src, pool_dest, object, data, action='u', context=None):
         self.meta.setdefault(pool_src, {})
-        if not context:
-            context = {}
         if not object in self.meta[pool_src]:
             self.meta[pool_src][object] = pool_src.get(object).fields_get(cr, uid, context=context)
         fields = self.meta[pool_src][object]
@@ -221,8 +213,6 @@ class base_synchro(osv.osv_memory):
 
 
     def upload_download(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         start_date = time.strftime('%Y-%m-%d, %Hh %Mm %Ss')
         syn_obj = self.browse(cr, uid, ids, context=context)[0]
         pool = pooler.get_pool(cr.dbname)
@@ -260,8 +250,6 @@ Exceptions:
             return True
 
     def upload_download_multi_thread(self, cr, uid, data, context=None):
-        if not context:
-            context = {}
         threaded_synchronization = threading.Thread(target=self.upload_download, args=(cr, uid, data, context))
         threaded_synchronization.run()
         data_obj = self.pool.get('ir.model.data')
diff --git a/addons/board/board.py b/addons/board/board.py
index 0c51ae8632f..0a7cd030043 100644
--- a/addons/board/board.py
+++ b/addons/board/board.py
@@ -38,8 +38,6 @@ class board_board(osv.osv):
         @param ids: List of Board's IDs
         @return: arch of xml view.
         """
-        if not context:
-            context = {}
         board = self.pool.get('board.board').browse(cr, uid, ids, context=context)
         left = []
         right = []
@@ -81,8 +79,6 @@ class board_board(osv.osv):
                      dictionary must be with the form: {‘name_of_the_field’: value, ...}.
         @return: True
         """
-        if not context:
-            context = {}
         result = super(board_board, self).write(cr, uid, ids, vals, context=context)
 
         board = self.pool.get('board.board').browse(cr, uid, ids[0], context=context)
@@ -101,8 +97,6 @@ class board_board(osv.osv):
         @return: id of new created record of board.board.
         """
 
-        if not context:
-            context = {}
 
         if not 'name' in vals:
             return False
@@ -126,8 +120,6 @@ class board_board(osv.osv):
         @return: Dictionary of Fields, arch and toolbar.
         """
 
-        if not context:
-            context = {}
 
         res = {}
         res = super(board_board, self).fields_view_get(cr, user, view_id, view_type,\
diff --git a/addons/board/wizard/board_menu_create.py b/addons/board/wizard/board_menu_create.py
index 18eae8d1e3f..2b688962265 100644
--- a/addons/board/wizard/board_menu_create.py
+++ b/addons/board/wizard/board_menu_create.py
@@ -55,7 +55,7 @@ class board_menu_create(osv.osv_memory):
         @param ids: List of Board Menu Create's IDs
         @return: Dictionary {}.
         """
-        if not context:
+        if context is None:
             context = {}
 
         context_id = context and context.get('active_id', False) or False
diff --git a/addons/caldav/calendar.py b/addons/caldav/calendar.py
index b01b5f97cc3..d60b7f90e91 100644
--- a/addons/caldav/calendar.py
+++ b/addons/caldav/calendar.py
@@ -149,7 +149,7 @@ def get_attribute_mapping(cr, uid, calname, context=None):
         @param calname: Get Calendar name
         @param context: A standard dictionary for contextual values """
 
-    if not context:
+    if context is None:
         context = {}
     pool = pooler.get_pool(cr.dbname)
     field_obj = pool.get('basic.calendar.fields')
@@ -470,7 +470,7 @@ class CalDAV(object):
             @param vals: Get Values
             @param context: A standard dictionary for contextual values
         """
-        if not context:
+        if context is None:
             context = {}
         ids = []
         model_obj = self.pool.get(context.get('model'))
@@ -592,7 +592,7 @@ class Calendar(CalDAV, osv.osv):
     }
 
     def get_calendar_objects(self, cr, uid, ids, parent=None, domain=None, context=None):
-        if not context:
+        if context is None:
             context = {}
         if not domain:
             domain = []
@@ -622,7 +622,7 @@ class Calendar(CalDAV, osv.osv):
         
 
     def get_cal_max_modified(self, cr, uid, ids, parent=None, domain=None, context=None):
-        if not context:
+        if context is None:
             context = {}
         if not domain:
             domain = []
@@ -652,7 +652,7 @@ class Calendar(CalDAV, osv.osv):
             @param vobj: the type of object to export
             @return the ical data.
         """
-        if not context:
+        if context is None:
            context = {}
         ctx_model = context.get('model', None)
         ctx_res_id = context.get('res_id', None)
@@ -684,7 +684,7 @@ class Calendar(CalDAV, osv.osv):
             @param data_id: Get Data’s ID or False
             @param context: A standard dictionary for contextual values
         """
-        if not context:
+        if context is None:
             context = {}
         vals = []
         ical_data = content
@@ -1066,7 +1066,7 @@ class Timezone(CalDAV, osv.osv_memory):
             @param model: Get Model's name
             @param context: A standard dictionary for contextual values
         """
-        if not context:
+        if context is None:
             context = {}
         ctx = context.copy()
         ctx.update({'model': model})
@@ -1125,7 +1125,7 @@ class Alarm(CalDAV, osv.osv_memory):
             @param alarm_id: Get Alarm's Id
             @param context: A standard dictionary for contextual values
         """
-        if not context:
+        if context is None:
             context = {}
         valarm = vevent.add('valarm')
         alarm_object = self.pool.get(model)
@@ -1246,7 +1246,7 @@ class Attendee(CalDAV, osv.osv_memory):
             @param attendee_ids: Get Attendee's Id
             @param context: A standard dictionary for contextual values
         """
-        if not context:
+        if context is None:
             context = {}
         attendee_object = self.pool.get(model)
         ctx = context.copy()
diff --git a/addons/caldav/calendar_collection.py b/addons/caldav/calendar_collection.py
index 828927668cd..1258ba5bf18 100644
--- a/addons/caldav/calendar_collection.py
+++ b/addons/caldav/calendar_collection.py
@@ -35,8 +35,6 @@ class calendar_collection(osv.osv):
     }
     
     def _get_root_calendar_directory(self, cr, uid, context=None):
-        if not context:
-            context = {}
         objid = self.pool.get('ir.model.data')
         try:
             mid = objid._get_id(cr, uid, 'document', 'dir_calendars')
@@ -52,8 +50,6 @@ class calendar_collection(osv.osv):
         return False
 
     def get_node_class(self, cr, uid, ids, dbro=None, dynamic=False, context=None):
-        if not context:
-            context = {}
         if dbro is None:
             dbro = self.browse(cr, uid, ids, context=context)
 
@@ -69,13 +65,9 @@ class calendar_collection(osv.osv):
 
     def get_description(self, cr, uid, ids, context=None):
         #TODO : return description of all calendars
-        if not context:
-            context = {}
         return False
 
     def get_schedule_inbox_URL(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         calendar_obj = self.pool.get('basic.calendar')
 
         calendar_ids = calendar_obj.search(cr, uid, [
diff --git a/addons/crm/crm.py b/addons/crm/crm.py
index 0382cb12564..2d4f997fc91 100644
--- a/addons/crm/crm.py
+++ b/addons/crm/crm.py
@@ -53,7 +53,7 @@ class crm_case(object):
         @param uid: the current user’s ID for security checks,
         @param context: A standard dictionary for contextual values
         """
-        if not context:
+        if context is None:
             context = {}
         if not context.get('portal', False):
             return False
@@ -66,7 +66,7 @@ class crm_case(object):
         @param uid: the current user’s ID for security checks,
         @param context: A standard dictionary for contextual values
         """
-        if not context:
+        if context is None:
             context = {}
         if not context.get('portal', False):
             return False
@@ -136,8 +136,6 @@ class crm_case(object):
         @param uid: the current user’s ID for security checks,
         @param context: A standard dictionary for contextual values
         """
-        if not context:
-            context = {}
         user = self.pool.get('res.users').browse(cr, uid, uid, context=context)
         return user.context_section_id.id or False
 
@@ -149,8 +147,6 @@ class crm_case(object):
         @param uid: the current user’s ID for security checks,
         @param ids: List of case IDs
         @param context: A standard dictionary for contextual values"""
-        if not context:
-            context = {}
         stage_pool = self.pool.get('crm.case.stage')
         model = self._name
         for case in self.browse(cr, uid, ids, context=context):
@@ -183,8 +179,6 @@ class crm_case(object):
         @param uid: the current user’s ID for security checks,
         @param ids: List of case IDs
         @param context: A standard dictionary for contextual values"""
-        if not context:
-            context = {}
         stage_pool = self.pool.get('crm.case.stage')
         model = self._name
         for case in self.browse(cr, uid, ids, context=context):
@@ -384,8 +378,6 @@ class crm_case(object):
         @param context: A standard dictionary for contextual values
 
         """
-        if not context:
-            context = {}
         for case in self.browse(cr, uid, ids, context=context):
             if not case.section_id.reply_to:
                 raise osv.except_osv(_('Error!'), ("Reply To is not specified in the sales team"))
@@ -450,7 +442,7 @@ class crm_case(object):
         return self._action(cr, uid, cases, False, context=context)
 
     def _action(self, cr, uid, cases, state_to, scrit=None, context=None):
-        if not context:
+        if context is None:
             context = {}
         context['state_to'] = state_to
         rule_obj = self.pool.get('base.action.rule')
@@ -469,8 +461,6 @@ class crm_case(object):
         """ Get a list of emails of the people following this thread
         """
         res = {}
-        if not context:
-            context = {}
         for case in self.browse(cr, uid, ids, context=context):
             l=[]
             if case.email_cc:
@@ -587,7 +577,7 @@ class crm_case_section(osv.osv):
         @param uid: the current user’s ID for security checks,
         @param ids: List of sales team ids
         """
-        if not context:
+        if context is None:
             context = {}
 
         res = []
@@ -661,8 +651,6 @@ def _links_get(self, cr, uid, context=None):
     @param uid: the current user’s ID for security checks,
     @param context: A standard dictionary for contextual values
     """
-    if not context:
-        context = {}
     obj = self.pool.get('res.request.link')
     ids = obj.search(cr, uid, [])
     res = obj.read(cr, uid, ids, ['object', 'name'], context)
diff --git a/addons/crm/crm_action_rule.py b/addons/crm/crm_action_rule.py
index 0c8d6ac492f..477f9132fab 100644
--- a/addons/crm/crm_action_rule.py
+++ b/addons/crm/crm_action_rule.py
@@ -51,8 +51,6 @@ this if you want the rule to send an email to the partner."),
     
 
     def email_send(self, cr, uid, obj, emails, body, emailfrom=tools.config.get('email_from', False), context=None):
-        if not context:
-            context = {}
         body = self.format_mail(obj, body)
         if not emailfrom:
             if hasattr(obj, 'user_id')  and obj.user_id and obj.user_id.address_id and obj.user_id.address_id.email:
@@ -74,8 +72,6 @@ this if you want the rule to send an email to the partner."),
         @param cr: the current row, from the database cursor,
         @param uid: the current user’s ID for security checks,
         @param context: A standard dictionary for contextual values"""
-        if not context:
-            context = {}
         ok = super(base_action_rule, self).do_check(cr, uid, action, obj, context=context)
 
         if hasattr(obj, 'section_id'):
@@ -111,8 +107,6 @@ this if you want the rule to send an email to the partner."),
         @param cr: the current row, from the database cursor,
         @param uid: the current user’s ID for security checks,
         @param context: A standard dictionary for contextual values """
-        if not context:
-            context = {}
         res = super(base_action_rule, self).do_action(cr, uid, action, model_obj, obj, context=context)
         write = {}
         
@@ -150,8 +144,6 @@ this if you want the rule to send an email to the partner."),
         @param cr: the current row, from the database cursor,
         @param uid: the current user’s ID for security checks,
         @param context: A standard dictionary for contextual values """
-        if not context:
-            context = {}
         res = super(base_action_rule, self).state_get(cr, uid, context=context)
         return res  + crm.AVAILABLE_STATES
 
@@ -160,8 +152,6 @@ this if you want the rule to send an email to the partner."),
         @param cr: the current row, from the database cursor,
         @param uid: the current user’s ID for security checks,
         @param context: A standard dictionary for contextual values """
-        if not context:
-            context = {}
         res = super(base_action_rule, self).priority_get(cr, uid, context=context)
         return res + crm.AVAILABLE_PRIORITIES
 
diff --git a/addons/crm/crm_installer.py b/addons/crm/crm_installer.py
index 7c068c9cabc..32551d438c4 100644
--- a/addons/crm/crm_installer.py
+++ b/addons/crm/crm_installer.py
@@ -40,8 +40,6 @@ class crm_installer(osv.osv_memory):
     }
 
     def fields_view_get(self, cr, uid, view_id=None, view_type='form', context=None, toolbar=False, submenu=False):
-        if not context:
-            context = {}
         res = super(crm_installer, self).fields_view_get(cr, uid, view_id=view_id, view_type=view_type, context=context, toolbar=toolbar,submenu=False)
         #Checking sale module is installed or not
         cr.execute("SELECT * from ir_module_module where state='installed' and name = 'sale'")
diff --git a/addons/crm/crm_lead.py b/addons/crm/crm_lead.py
index ee649c18dc9..6522085be9b 100644
--- a/addons/crm/crm_lead.py
+++ b/addons/crm/crm_lead.py
@@ -53,8 +53,6 @@ class crm_lead(crm_case, osv.osv):
         res_obj = self.pool.get('resource.resource')
 
         res = {}
-        if not context:
-            context = {}
         for lead in self.browse(cr, uid, ids, context=context):
             for field in fields:
                 res[lead.id] = {}
@@ -237,7 +235,7 @@ class crm_lead(crm_case, osv.osv):
         @param context: A standard dictionary for contextual values
         @return: Value of action in dict
         """
-        if not context:
+        if context is None:
             context = {}
         context.update({'active_ids': ids})
 
@@ -321,8 +319,6 @@ class crm_lead(crm_case, osv.osv):
         @param cr: the current row, from the database cursor,
         @param uid: the current user’s ID for security checks
         """
-        if not context:
-            context = {}
         mailgate_pool = self.pool.get('email.server.tools')
 
         subject = msg.get('subject')
@@ -366,8 +362,6 @@ class crm_lead(crm_case, osv.osv):
         @param uid: the current user’s ID for security checks,
         @param ids: List of update mail’s IDs 
         """
-        if not context:
-            context = {}
         if isinstance(ids, (str, int, long)):
             ids = [ids]
 
diff --git a/addons/crm/crm_meeting.py b/addons/crm/crm_meeting.py
index d6ec3d7f9cd..cb18b1fe270 100644
--- a/addons/crm/crm_meeting.py
+++ b/addons/crm/crm_meeting.py
@@ -91,9 +91,6 @@ class crm_meeting(crm_case, osv.osv):
         @return: Dictionary value which open Crm Meeting form.
         """
 
-        if not context:
-            context = {}
-
         data_obj = self.pool.get('ir.model.data')
 
         value = {}
@@ -154,8 +151,6 @@ class calendar_attendee(osv.osv):
         @param context: A standard dictionary for contextual values
         """
        name = name[0]
-       if not context:
-            context = {}
        result = super(calendar_attendee, self)._compute_data(cr, uid, ids, name, arg, context=context)
 
        for attdata in self.browse(cr, uid, ids, context=context):
diff --git a/addons/crm/crm_opportunity.py b/addons/crm/crm_opportunity.py
index eeca1a6cb50..3c2f1ba2050 100644
--- a/addons/crm/crm_opportunity.py
+++ b/addons/crm/crm_opportunity.py
@@ -145,9 +145,6 @@ class crm_opportunity(osv.osv):
         if not stage_id:
             return {'value':{}}
         
-        if not context:
-            context = {}
-
         stage = self.pool.get('crm.case.stage').browse(cr, uid, stage_id, context=context)
 
         if not stage.on_change:
@@ -171,8 +168,6 @@ class crm_opportunity(osv.osv):
         @return : Dictionary value for created Meeting view
         """
         value = {}
-        if not context:
-            context = {}
         for opp in self.browse(cr, uid, ids, context=context):
             data_obj = self.pool.get('ir.model.data')
 
diff --git a/addons/crm/crm_phonecall.py b/addons/crm/crm_phonecall.py
index 1ad8878f0d4..2b2066f6eb2 100644
--- a/addons/crm/crm_phonecall.py
+++ b/addons/crm/crm_phonecall.py
@@ -157,8 +157,6 @@ class crm_phonecall(crm_case, osv.osv):
         @return : Dictionary value for created Meeting view
         """
         value = {}
-        if not context:
-            context = {}
         for phonecall in self.browse(cr, uid, ids, context=context):
             data_obj = self.pool.get('ir.model.data')
 
diff --git a/addons/crm/wizard/crm_add_note.py b/addons/crm/wizard/crm_add_note.py
index 6bdf472cd97..3c57156a23f 100644
--- a/addons/crm/wizard/crm_add_note.py
+++ b/addons/crm/wizard/crm_add_note.py
@@ -19,7 +19,7 @@ class crm_add_note(osv.osv_memory):
     }
 
     def action_add(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
 
         if not context.get('active_model'):
diff --git a/addons/crm/wizard/crm_lead_to_opportunity.py b/addons/crm/wizard/crm_lead_to_opportunity.py
index 5e1c8ae946b..b008939ef95 100644
--- a/addons/crm/wizard/crm_lead_to_opportunity.py
+++ b/addons/crm/wizard/crm_lead_to_opportunity.py
@@ -122,7 +122,7 @@ class crm_lead2opportunity(osv.osv_memory):
         @param context: A standard dictionary for contextual values
 
         """
-        if not context:
+        if context is None:
             context = {}
         lead_obj = self.pool.get('crm.lead')
 
@@ -177,7 +177,7 @@ class crm_lead2opportunity_partner(osv.osv_memory):
 
         @return : Dictionary value for created Partner form.
         """
-        if not context:
+        if context is None:
             context = {}
 
         partner_ids = self._create_partner(cr, uid, ids, context=context)
@@ -214,7 +214,7 @@ class crm_lead2opportunity_partner(osv.osv_memory):
         @return : Dictionary value for Opportunity form
         """
         value = {}
-        if not context:
+        if context is None:
             context = {}
         data_obj = self.pool.get('ir.model.data')
         data_id = data_obj._get_id(cr, uid, 'crm', 'view_crm_lead2opportunity_create')
@@ -247,7 +247,7 @@ class crm_lead2opportunity_partner(osv.osv_memory):
         @param context: A standard dictionary for contextual values
 
         """
-        if not context:
+        if context is None:
             context = {}
         lead_obj = self.pool.get('crm.lead')
 
@@ -282,7 +282,7 @@ class crm_lead2opportunity_action(osv.osv_memory):
         @return : Dictionary value for Opportunity form
         """
         value = {}
-        if not context:
+        if context is None:
             context = {}
         data_obj = self.pool.get('ir.model.data')
         view_id = False
diff --git a/addons/crm/wizard/crm_lead_to_partner.py b/addons/crm/wizard/crm_lead_to_partner.py
index e21580a9522..08e75874d67 100644
--- a/addons/crm/wizard/crm_lead_to_partner.py
+++ b/addons/crm/wizard/crm_lead_to_partner.py
@@ -135,7 +135,7 @@ class crm_lead2partner(osv.osv_memory):
 
         @return : Dictionary value for next form.
         """
-        if not context:
+        if context is None:
             context = {}
 
         view_obj = self.pool.get('ir.ui.view')
@@ -163,7 +163,7 @@ class crm_lead2partner(osv.osv_memory):
 
         @return : Dictionary {}.
         """
-        if not context:
+        if context is None:
             context = {}
 
         lead_obj = self.pool.get('crm.lead')
@@ -226,7 +226,7 @@ class crm_lead2partner(osv.osv_memory):
 
         @return : Dictionary value for created Partner form.
         """
-        if not context:
+        if context is None:
             context = {}
 
         partner_ids = self._create_partner(cr, uid, ids, context=context)
diff --git a/addons/crm/wizard/crm_phonecall_to_meeting.py b/addons/crm/wizard/crm_phonecall_to_meeting.py
index bbad4644168..06c46b8bf55 100644
--- a/addons/crm/wizard/crm_phonecall_to_meeting.py
+++ b/addons/crm/wizard/crm_phonecall_to_meeting.py
@@ -32,7 +32,7 @@ import pooler
 class phonecall2meeting(wizard.interface):
 
     def _makeMeeting(self, cr, uid, data, context=None):
-        if not context:
+        if context is None:
             context = {}
         pool = pooler.get_pool(cr.dbname)
         phonecall_case_obj = pool.get('crm.phonecall')                   
diff --git a/addons/crm/wizard/crm_phonecall_to_partner.py b/addons/crm/wizard/crm_phonecall_to_partner.py
index ac411f1c5ce..38e673108e4 100644
--- a/addons/crm/wizard/crm_phonecall_to_partner.py
+++ b/addons/crm/wizard/crm_phonecall_to_partner.py
@@ -63,7 +63,7 @@ class crm_phonecall2partner(osv.osv_memory):
 
         @return : Partner id if any for selected phonecall.
         """
-        if not context:
+        if context is None:
             context = {}
 
         phonecall_obj = self.pool.get('crm.phonecall')
@@ -99,8 +99,6 @@ class crm_phonecall2partner(osv.osv_memory):
 
         @return : Dictionary value for next form.
         """
-        if not context:
-            context = {}
 
         view_obj = self.pool.get('ir.ui.view')
         view_id = view_obj.search(cr, uid, [('model', '=', 'crm.phonecall2partner'), \
@@ -127,7 +125,7 @@ class crm_phonecall2partner(osv.osv_memory):
 
         @return : Dictionary {}.
         """
-        if not context:
+        if context is None:
             context = {}
 
         phonecall_obj = self.pool.get('crm.phonecall')
@@ -178,8 +176,6 @@ class crm_phonecall2partner(osv.osv_memory):
 
         @return : Dictionary value for created Partner form.
         """
-        if not context:
-            context = {}
 
         partner_ids = self._create_partner(cr, uid, ids, context=context)
         mod_obj = self.pool.get('ir.model.data')
diff --git a/addons/crm/wizard/crm_send_email.py b/addons/crm/wizard/crm_send_email.py
index 95bc978be73..eeb635b7c3b 100644
--- a/addons/crm/wizard/crm_send_email.py
+++ b/addons/crm/wizard/crm_send_email.py
@@ -65,7 +65,7 @@ class crm_send_new_email(osv.osv_memory):
         """
         hist_obj = self.pool.get('mailgate.message')
 
-        if not context:
+        if context is None:
             context = {}
 
         if not context.get('active_model'):
@@ -162,7 +162,7 @@ class crm_send_new_email(osv.osv_memory):
         """
         This function gets default values
         """
-        if not context:
+        if context is None:
             context = {}
 
         if not context.get('active_model'):
@@ -263,7 +263,7 @@ class crm_send_new_email(osv.osv_memory):
         @param context: A standard dictionary for contextual values
 
         """
-        if not context:
+        if context is None:
             context = {}
 
         if not context.get('active_model'):
diff --git a/addons/crm/wizard/wizard_history_event.py b/addons/crm/wizard/wizard_history_event.py
index 5e1ea1e3ba0..b71ee0d6cd0 100644
--- a/addons/crm/wizard/wizard_history_event.py
+++ b/addons/crm/wizard/wizard_history_event.py
@@ -25,8 +25,6 @@ import pooler
 import time
 
 def _open_history_event(self, cr, uid, data, context=None):
-    if not context:
-        context = {} 
     pool = pooler.get_pool(cr.dbname)
     data_obj = pool.get('ir.model.data')
     result = data_obj._get_id(cr, uid, 'crm', 'view_crm_case_filter')
diff --git a/addons/crm_caldav/crm_caldav.py b/addons/crm_caldav/crm_caldav.py
index c2ed193dc23..8ba59909143 100644
--- a/addons/crm_caldav/crm_caldav.py
+++ b/addons/crm_caldav/crm_caldav.py
@@ -36,8 +36,7 @@ class crm_meeting(osv.osv):
             @param ids: List of CRM Meeting’s IDs
             @param context: A standard dictionary for contextual values
         """
-        if not context:
-            context = {}
+        if context is None: context = {}
         ids = map(lambda x: base_calendar.base_calendar_id2real_id(x), ids)
         event_data = self.read(cr, uid, ids, context=context)
         event_obj = self.pool.get('basic.calendar.event')
@@ -54,8 +53,6 @@ class crm_meeting(osv.osv):
             @param data_id: calendar's Id
             @param context: A standard dictionary for contextual values
         """
-        if not context:
-            context = {}
         event_obj = self.pool.get('basic.calendar.event')
         vals = event_obj.import_cal(cr, uid, data, context=context)
         return self.check_import(cr, uid, vals, context=context)
@@ -68,7 +65,7 @@ class crm_meeting(osv.osv):
             @param vals: Get Values
             @param context: A standard dictionary for contextual values
         """
-        if not context:
+        if context is None:
             context = {}
         ids = []
         model_obj = self.pool.get(context.get('model'))
diff --git a/addons/crm_partner_assign/partner_geo_assign.py b/addons/crm_partner_assign/partner_geo_assign.py
index 83cbc9717eb..bc3a9795834 100644
--- a/addons/crm_partner_assign/partner_geo_assign.py
+++ b/addons/crm_partner_assign/partner_geo_assign.py
@@ -71,8 +71,6 @@ class res_partner(osv.osv):
         'partner_weight': lambda *args: 0
     }
     def geo_localize(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for partner in self.browse(cr, uid, ids, context=context):
             if not partner.address:
                 continue
@@ -111,8 +109,6 @@ class crm_lead(osv.osv):
 
     def assign_partner(self, cr, uid, ids, context=None):
         ok = False
-        if not context:
-            context = {}
         for part in self.browse(cr, uid, ids, context=context):
             if not part.country_id:
                 continue
diff --git a/addons/crm_partner_assign/wizard/crm_forward_to_partner.py b/addons/crm_partner_assign/wizard/crm_forward_to_partner.py
index 1ee6b355b6a..fdb7acff35c 100644
--- a/addons/crm_partner_assign/wizard/crm_forward_to_partner.py
+++ b/addons/crm_partner_assign/wizard/crm_forward_to_partner.py
@@ -169,7 +169,7 @@ class crm_lead_forward_to_partner(osv.osv_memory):
         """
         Forward the lead to a partner
         """
-        if not context:
+        if context is None:
             context = {}
         this = self.browse(cr, uid, ids[0], context=context)
         case_pool = self.pool.get(context.get('active_model'))
@@ -202,8 +202,6 @@ class crm_lead_forward_to_partner(osv.osv_memory):
 
     def get_lead_details(self, cr, uid, lead_id, context=None):
         body = []
-        if not context:
-            context = {}
         lead_proxy = self.pool.get('crm.lead')
         lead = lead_proxy.browse(cr, uid, lead_id, context=context)
         if not lead.type or lead.type == 'lead' or not lead.partner_address_id:
diff --git a/addons/crm_profiling/crm_profiling.py b/addons/crm_profiling/crm_profiling.py
index 6db0e06f9d9..20b9b585e34 100644
--- a/addons/crm_profiling/crm_profiling.py
+++ b/addons/crm_profiling/crm_profiling.py
@@ -167,8 +167,6 @@ class questionnaire(osv.osv):
             @param data: Get Data
             @param context: A standard dictionary for contextual values """
         
-        if not context:
-            context = {}
         query = """
         select name, id
         from crm_profiling_question
@@ -221,8 +219,6 @@ class partner(osv.osv):
             @param context: A standard dictionary for contextual values """
 
         temp = []
-        if not context:
-            context = {}
         for x in data['form']:
             if x.startswith("quest_form") and data['form'][x] != 0 :
                 temp.append(data['form'][x])
@@ -244,8 +240,6 @@ class partner(osv.osv):
             @param ids: List of crm profiling’s IDs
             @param context: A standard dictionary for contextual values """
 
-        if not context:
-            context={}
         if 'answers_ids' in vals:
             vals['category_id']=[[6, 0, _recompute_categ(self, cr, uid, ids[0], vals['answers_ids'][0][2])]]
         return super(partner, self).write(cr, uid, ids, vals, context=context)
diff --git a/addons/delivery/delivery.py b/addons/delivery/delivery.py
index f0d907461c3..aae6f566b69 100644
--- a/addons/delivery/delivery.py
+++ b/addons/delivery/delivery.py
@@ -30,7 +30,7 @@ class delivery_carrier(osv.osv):
     def name_get(self, cr, uid, ids, context=None):
         if not len(ids):
             return []
-        if not context:
+        if context is None:
             context = {}
         order_id = context.get('order_id',False)
         if not order_id:
@@ -42,7 +42,7 @@ class delivery_carrier(osv.osv):
         return res
     def get_price(self, cr, uid, ids, field_name, arg=None, context=None):
         res={}
-        if not context:
+        if context is None:
             context = {}
         sale_obj=self.pool.get('sale.order')
         grid_obj=self.pool.get('delivery.grid')
@@ -70,8 +70,6 @@ class delivery_carrier(osv.osv):
         'active': lambda *args:1
     }
     def grid_get(self, cr, uid, ids, contact_id, context=None):
-        if not context:
-            context = {}
         contact = self.pool.get('res.partner.address').browse(cr, uid, [contact_id], context=context)[0]
         for carrier in self.browse(cr, uid, ids, context=context):
             for grid in carrier.grids_id:
@@ -114,8 +112,6 @@ class delivery_grid(osv.osv):
         total = 0
         weight = 0
         volume = 0
-        if not context:
-            context = {}
         for line in order.order_line:
             if not line.product_id:
                 continue
diff --git a/addons/delivery/stock.py b/addons/delivery/stock.py
index 9fe51b04256..5614248a001 100644
--- a/addons/delivery/stock.py
+++ b/addons/delivery/stock.py
@@ -30,8 +30,6 @@ class stock_picking(osv.osv):
 
     def _cal_weight(self, cr, uid, ids, name, args, context=None):
         res = {}
-        if not context:
-            context = {}
         uom_obj = self.pool.get('product.uom')
         for picking in self.browse(cr, uid, ids, context=context):
             total_weight = total_weight_net = 0.00
@@ -78,9 +76,6 @@ class stock_picking(osv.osv):
         grid_obj = self.pool.get('delivery.grid')
         invoice_line_obj = self.pool.get('account.invoice.line')
         
-        if not context:
-            context = {}
-
         result = super(stock_picking, self).action_invoice_create(cursor, user,
                 ids, journal_id=journal_id, group=group, type=type,
                 context=context)
@@ -142,8 +137,6 @@ class stock_move(osv.osv):
 
     def _cal_move_weight(self, cr, uid, ids, name, args, context=None):
         res = {}
-        if not context:
-            context = {}
         uom_obj = self.pool.get('product.uom')
         for move in self.browse(cr, uid, ids, context=context):
             weight = weight_net = 0.00
diff --git a/addons/delivery/wizard/delivery_sale_order.py b/addons/delivery/wizard/delivery_sale_order.py
index 3a2f52337d6..f20426bbc35 100644
--- a/addons/delivery/wizard/delivery_sale_order.py
+++ b/addons/delivery/wizard/delivery_sale_order.py
@@ -47,8 +47,6 @@ class make_delivery(osv.osv_memory):
              @return: A dictionary which of fields with values. 
         
         """
-        if not context:
-            context = {}        
         res = super(make_delivery, self).default_get(cr, uid, fields, context=context)
         order_obj = self.pool.get('sale.order')
         for order in order_obj.browse(cr, uid, context.get('active_ids', []), context=context):
@@ -60,7 +58,7 @@ class make_delivery(osv.osv_memory):
         return res
     
     def view_init(self, cr , uid , fields, context=None):
-         if not context:
+         if context is None:
             context = {}
          order_obj = self.pool.get('sale.order')
          for order in order_obj.browse(cr, uid, context.get('active_ids', []), context=context):     
@@ -81,7 +79,7 @@ class make_delivery(osv.osv_memory):
              @return:  
         
         """
-        if not context:
+        if context is None:
             context = {}
         rec_ids = context and context.get('active_ids',[])
         order_obj = self.pool.get('sale.order')
diff --git a/addons/document/directory_content.py b/addons/document/directory_content.py
index 8c0c9e0e88b..cd0c44584a7 100644
--- a/addons/document/directory_content.py
+++ b/addons/document/directory_content.py
@@ -110,7 +110,7 @@ class document_directory_content(osv.osv):
         return True
     
     def process_read(self, cr, uid, node, context=None):
-        if not context:
+        if context is None:
             context = {}
         if node.extension != '.pdf':
             raise Exception("Invalid content: %s" % node.extension)
diff --git a/addons/document/directory_report.py b/addons/document/directory_report.py
index 97d70e1a3cb..6eb18dae850 100644
--- a/addons/document/directory_report.py
+++ b/addons/document/directory_report.py
@@ -28,8 +28,6 @@ class ir_action_report_xml(osv.osv):
 
     def _model_get(self, cr, uid, ids, name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         model_pool = self.pool.get('ir.model')
         for data in self.read(cr, uid, ids, ['model']):
             model = data.get('model',False)
diff --git a/addons/document/document.py b/addons/document/document.py
index 0ccd0ec51ec..7e575f38a37 100644
--- a/addons/document/document.py
+++ b/addons/document/document.py
@@ -39,7 +39,7 @@ class document_file(osv.osv):
         return os.path.join(DMS_ROOT_PATH, cr.dbname)
 
     def _data_get(self, cr, uid, ids, name, arg, context=None):
-        if not context:
+        if context is None:
             context = {}
         fbrl = self.browse(cr, uid, ids, context=context)
         nctx = nodes.get_node_context(cr, uid, context={})
@@ -64,8 +64,6 @@ class document_file(osv.osv):
     def _data_set(self, cr, uid, id, name, value, arg, context=None):
         if not value:
             return True
-        if not context:
-            context = {}
         fbro = self.browse(cr, uid, id, context=context)
         nctx = nodes.get_node_context(cr, uid, context={})
         fnode = nodes.node_file(None, None, nctx, fbro)
@@ -140,8 +138,6 @@ class document_file(osv.osv):
     def copy(self, cr, uid, id, default=None, context=None):
         if not default:
             default = {}
-        if not context:
-            context = {}
         if 'name' not in default:
             name = self.read(cr, uid, [id])[0]['name']
             default.update({'name': name + " (copy)"})
@@ -233,8 +229,6 @@ class document_file(osv.osv):
             It is a hack that will try to discover if the mentioned record is
             clearly associated with a partner record.
         """
-        if not context:
-            context = {}
         obj_model = self.pool.get(res_model)
         if obj_model._name == 'res.partner':
             return res_id
@@ -249,8 +243,6 @@ class document_file(osv.osv):
     def unlink(self, cr, uid, ids, context=None):
         stor = self.pool.get('document.storage')
         unres = []
-        if not context:
-            context = {}
         # We have to do the unlink in 2 stages: prepare a list of actual
         # files to be unlinked, update the db (safer to do first, can be
         # rolled back) and then unlink the files. The list wouldn't exist
diff --git a/addons/document/document_directory.py b/addons/document/document_directory.py
index a8a54955b74..1f7d1e15807 100644
--- a/addons/document/document_directory.py
+++ b/addons/document/document_directory.py
@@ -175,8 +175,6 @@ class document_directory(osv.osv):
         """ Return a node object for the given uri.
            This fn merely passes the call to node_context
         """
-        if not context:
-                context = {}
 
         return nodes.get_node_context(cr, uid, context).get_uri(cr, uri)
 
@@ -186,8 +184,6 @@ class document_directory(osv.osv):
            This function can be overriden by inherited classes ;)
            @param dbro The browse object, if caller already has it
         """
-        if not context:
-            context = {}
         if dbro is None:
             dbro = self.browse(cr, uid, ids, context=context)
 
@@ -237,8 +233,6 @@ class document_directory(osv.osv):
     def copy(self, cr, uid, id, default=None, context=None):
         if not default:
             default ={}
-        if not context:
-            context = {}
         name = self.read(cr, uid, [id])[0]['name']
         default.update({'name': name+ " (copy)"})
         return super(document_directory,self).copy(cr, uid, id, default, context=context)
diff --git a/addons/document/document_storage.py b/addons/document/document_storage.py
index eaa4244f10f..b61b7fd65fc 100644
--- a/addons/document/document_storage.py
+++ b/addons/document/document_storage.py
@@ -422,9 +422,7 @@ class document_storage(osv.osv):
             optionally, fil_obj could point to the browse object of the file
             (ir.attachment)
         """
-        if not context:
-            context = {}
-        boo = self.browse(cr, uid, id, context)
+        boo = self.browse(cr, uid, id, context=context)
         if not boo.online:
             raise IOError(errno.EREMOTE, 'medium offline')
         
@@ -540,8 +538,6 @@ class document_storage(osv.osv):
             This function MUST be used from an ir.attachment. It wouldn't make sense
             to store things persistently for other types (dynamic).
         """
-        if not context:
-            context = {}
         boo = self.browse(cr, uid, id, context=context)
         if fil_obj:
             ira = fil_obj
@@ -688,8 +684,6 @@ class document_storage(osv.osv):
             
             @return the dict of values that can safely be be stored in the db.
         """
-        if not context:
-            context = {}
         sbro = self.browse(cr, uid, file_node.storage_id, context=context)
         assert sbro, "The file #%d didn't provide storage" % file_node.file_id
 
@@ -732,8 +726,6 @@ class document_storage(osv.osv):
                     file should move to.
             @return the dict of values that can safely be be stored in the db.
         """
-        if not context:
-            context = {}
         sbro = self.browse(cr, uid, file_node.storage_id, context=context)
         assert sbro, "The file #%d didn't provide storage" % file_node.file_id
 
diff --git a/addons/document/wizard/document_configuration.py b/addons/document/wizard/document_configuration.py
index bc25e6bdc44..26ce8652599 100644
--- a/addons/document/wizard/document_configuration.py
+++ b/addons/document/wizard/document_configuration.py
@@ -33,8 +33,6 @@ class document_configuration(osv.osv_memory):
     
 
     def execute(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         conf_id = ids and ids[0] or False
         conf = self.browse(cr, uid, conf_id, context=context)
         dir_pool = self.pool.get('document.directory')
diff --git a/addons/document_ftp/wizard/ftp_browse.py b/addons/document_ftp/wizard/ftp_browse.py
index b1a8bc01b73..3e5787819b2 100644
--- a/addons/document_ftp/wizard/ftp_browse.py
+++ b/addons/document_ftp/wizard/ftp_browse.py
@@ -33,8 +33,6 @@ class document_ftp_browse(osv.osv_memory):
 
     def default_get(self, cr, uid, fields, context=None):
         res = {}
-        if not context:
-            context = {}
         if 'url' in fields:
             user_pool = self.pool.get('res.users')
             current_user = user_pool.browse(cr, uid, uid, context=context)
@@ -52,8 +50,6 @@ class document_ftp_browse(osv.osv_memory):
 
     def browse_ftp(self, cr, uid, ids, context=None):
         data_id = ids and ids[0] or False
-        if not context:
-            context = {}
         data = self.browse(cr, uid, data_id, context=context)
         final_url = data.url
         return {
diff --git a/addons/document_ftp/wizard/ftp_configuration.py b/addons/document_ftp/wizard/ftp_configuration.py
index 43442a0ed45..17dc99d202e 100644
--- a/addons/document_ftp/wizard/ftp_configuration.py
+++ b/addons/document_ftp/wizard/ftp_configuration.py
@@ -39,8 +39,6 @@ class document_ftp_configuration(osv.osv_memory):
     }
 
     def execute(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         conf = self.browse(cr, uid, ids[0], context=context)
         data_pool = self.pool.get('ir.model.data')
         # Update the action for FTP browse.
diff --git a/addons/document_ics/document_ics.py b/addons/document_ics/document_ics.py
index 9133a525afa..82a672c2006 100644
--- a/addons/document_ics/document_ics.py
+++ b/addons/document_ics/document_ics.py
@@ -347,7 +347,7 @@ class crm_meeting(osv.osv):
         """
 
         if not default: default = {}
-        if not context: context = {}
+        if context is None: context = {}
         default.update({'code': self.pool.get('ir.sequence').get(cr, uid, 'crm.meeting'), 'id': False})
         return super(crm_meeting, self).copy(cr, uid, id, default, context)
 
diff --git a/addons/document_webdav/document_webdav.py b/addons/document_webdav/document_webdav.py
index b06032089aa..d2107e4f927 100644
--- a/addons/document_webdav/document_webdav.py
+++ b/addons/document_webdav/document_webdav.py
@@ -46,8 +46,6 @@ class document_davdir(osv.osv):
             raise ValueError("dir node for %s type", dbro.type)
 
     def _prepare_context(self, cr, uid, nctx, context=None):
-        if not context:
-            context = {}
         nctx.node_file_class = nodes.node_file
         # We can fill some more fields, but avoid any expensive function
         # that might be not worth preparing.
diff --git a/addons/email_template/email_template.py b/addons/email_template/email_template.py
index b5e38532691..836fe5b77e4 100644
--- a/addons/email_template/email_template.py
+++ b/addons/email_template/email_template.py
@@ -72,8 +72,6 @@ def get_value(cursor, user, recid, message=None, template=None, context=None):
     @return: Computed message (unicode) or u""
     """
     pool = pooler.get_pool(cursor.dbname)
-    if not context:
-        context = {}
     if message is None:
         message = {}
     #Returns the computed expression
@@ -274,7 +272,7 @@ This is useful for CRM leads for example"),
 
     def create_action(self, cr, uid, ids, context=None):
         vals = {}
-        if not context:
+        if context is None:
             context = {}
         template_obj = self.browse(cr, uid, ids, context=context)[0]
         src_obj = template_obj.object_name.model
@@ -304,8 +302,6 @@ This is useful for CRM leads for example"),
         return True
 
     def unlink_action(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for template in self.browse(cr, uid, ids, context=context):
             try:
                 if template.ref_ir_act_window:
diff --git a/addons/email_template/email_template_account.py b/addons/email_template/email_template_account.py
index 6acf88d5e95..40ea0fd53c1 100644
--- a/addons/email_template/email_template_account.py
+++ b/addons/email_template/email_template_account.py
@@ -209,8 +209,6 @@ unless it is already specified in the From Email, e.g: John Doe <john@doe.com>",
         
         @return: SMTP server object or Exception
         """
-        if not context:
-            context = {}
         #Type cast ids to integer
         if type(ids) == list:
             ids = ids[0]
@@ -268,8 +266,6 @@ unless it is already specified in the From Email, e.g: John Doe <john@doe.com>",
         This method should now wrap smtp_connection
         """
         #This function returns a SMTP server object
-        if not context:
-            context = {}
         logger = netsvc.Logger()
         core_obj = self.browse(cursor, user, id, context=context)
         if core_obj.smtpserver and core_obj.smtpport and core_obj.state == 'approved':
diff --git a/addons/email_template/email_template_mailbox.py b/addons/email_template/email_template_mailbox.py
index 51d73ffc76c..738c9034366 100644
--- a/addons/email_template/email_template_mailbox.py
+++ b/addons/email_template/email_template_mailbox.py
@@ -196,8 +196,6 @@ class email_template_mailbox(osv.osv):
         It just changes the folder of the item to "Trash", if it is no in Trash folder yet, 
         or completely deletes it if it is already in Trash.
         """
-        if not context:
-            context = {}
         to_update = []
         to_remove = []
         for mail in self.browse(cr, uid, ids, context=context):
diff --git a/addons/event/event.py b/addons/event/event.py
index 25aa7425c10..84712d44c11 100644
--- a/addons/event/event.py
+++ b/addons/event/event.py
@@ -101,11 +101,11 @@ class event_event(osv.osv):
         @param context: A standard dictionary for contextual values
         @return: True
         """
-        if not context:
-            context = {}
         res = False
         if type(ids) in (int, long,):
             ids = [ids]
+        if context is None:
+            context = {}
         data_pool = self.pool.get('ir.model.data')
         unconfirmed_ids = []
         for event in self.browse(cr, uid, ids, context=context):
@@ -141,8 +141,6 @@ class event_event(osv.osv):
         """
         register_pool = self.pool.get('event.registration')
         res = {}
-        if not context:
-            context = {}
         for event in self.browse(cr, uid, ids, context=context):
             res[event.id] = {}
             for field in fields:
@@ -394,7 +392,7 @@ class event_registration(osv.osv):
         inv_pool = self.pool.get('account.invoice')
         product_pool = self.pool.get('product.product')
         contact_pool = self.pool.get('res.partner.contact')
-        if not context:
+        if context is None:
             context = {}
         # If date was specified, use it as date invoiced, usefull when invoices are generated this month and put the
         # last day of the last month as invoice date
@@ -450,7 +448,7 @@ class event_registration(osv.osv):
     def do_close(self, cr, uid, ids, context=None):
         """ Close Registration
         """
-        if not context:
+        if context is None:
             context = {}
         invoice_id = context.get('invoice_id', False)
         values = {'state': 'done', 'date_closed': time.strftime('%Y-%m-%d %H:%M:%S')}
@@ -467,12 +465,12 @@ class event_registration(osv.osv):
         @param context: A standard dictionary for contextual values
         @return: True
         """
-        if not context:
-            context = {}
         if type(ids) in (int, long,):
             ids = [ids]
         data_pool = self.pool.get('ir.model.data')
         unconfirmed_ids = []
+        if context is None:
+            context = {}
         for registration in self.browse(cr, uid, ids, context=context):
             total_confirmed = registration.event_id.register_current + registration.nb_register
             if total_confirmed <= registration.event_id.register_max or registration.event_id.register_max == 0:
@@ -500,10 +498,10 @@ class event_registration(osv.osv):
     def button_reg_close(self, cr, uid, ids, context=None):
         """This Function Close Event Registration.
         """
-        if not context:
-            context = {}
         data_pool = self.pool.get('ir.model.data')
         unclosed_ids = []
+        if context is None:
+            context = {}
         for registration in self.browse(cr, uid, ids, context=context):
             if registration.tobe_invoiced and not registration.invoice_id:
                 unclosed_ids.append(registration.id)
@@ -538,8 +536,6 @@ class event_registration(osv.osv):
         """
         Send email to user
         """
-        if not context:
-            context = {}
 
         for regestration in self.browse(cr, uid, ids, context=context):
             src = regestration.event_id.reply_to or False
diff --git a/addons/event/wizard/partner_event_registration.py b/addons/event/wizard/partner_event_registration.py
index d8639b4e646..b8521e404e2 100644
--- a/addons/event/wizard/partner_event_registration.py
+++ b/addons/event/wizard/partner_event_registration.py
@@ -105,8 +105,6 @@ class partner_event_registration(osv.osv_memory):
         """Overrides orm name_get method
         @param ids: List of partner_event_register ids
         """
-        if not context:
-            context = {}
 
         res = []
         if not ids:
@@ -124,7 +122,7 @@ class partner_event_registration(osv.osv_memory):
         event_obj = self.pool.get('event.event')
         product_obj = self.pool.get('product.product')
         partner_obj = self.pool.get('res.partner')
-        if not context:
+        if context is None:
             context = {}
         partner_id = context.get('active_id', False)
         if event_id:
diff --git a/addons/event_project/event_project.py b/addons/event_project/event_project.py
index b892835bb49..8590b84c4ad 100644
--- a/addons/event_project/event_project.py
+++ b/addons/event_project/event_project.py
@@ -24,8 +24,6 @@ from osv import fields, osv
 class one2many_mod_task(fields.one2many):
     
     def get(self, cr, obj, ids, name, user=None, offset=0, context=None, values=None):
-        if not context:
-            context = {}
         if not values:
                 values = {}
         res = {}
diff --git a/addons/event_project/wizard/event_project_retro.py b/addons/event_project/wizard/event_project_retro.py
index 799d952acf4..ada9b7fa17b 100644
--- a/addons/event_project/wizard/event_project_retro.py
+++ b/addons/event_project/wizard/event_project_retro.py
@@ -65,8 +65,6 @@ class event_project(osv.osv_memory):
     }
     
     def create_duplicate(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         event_obj = self.pool.get('event.event')
         project_obj = self.pool.get('project.project')
         event = event_obj.browse(cr, uid, context.get('active_id', False), context=context)
diff --git a/addons/fetchmail/fetchmail.py b/addons/fetchmail/fetchmail.py
index 295f8813047..05363819e15 100644
--- a/addons/fetchmail/fetchmail.py
+++ b/addons/fetchmail/fetchmail.py
@@ -100,7 +100,7 @@ class email_server(osv.osv):
         return True
     
     def button_confirm_login(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         for server in self.browse(cr, uid, ids, context=context):
             logger.notifyChannel('imap', netsvc.LOG_INFO, 'fetchmail start checking for new emails on %s' % (server.name))
@@ -147,7 +147,7 @@ class email_server(osv.osv):
         return self.fetch_mail(cr, uid, ids, context=context)
 
     def fetch_mail(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         email_tool = self.pool.get('email.server.tools')
         action_pool = self.pool.get('ir.actions.server')
@@ -209,7 +209,7 @@ class mailgate_message(osv.osv):
     _order = 'id desc'
 
     def create(self, cr, uid, values, context=None):
-        if not context:
+        if context is None:
             context={}
         server_id = context.get('server_id',False)
         server_type = context.get('server_type',False)
@@ -221,7 +221,7 @@ class mailgate_message(osv.osv):
         return res
 
     def write(self, cr, uid, ids, values, context=None):
-        if not context:
+        if context is None:
             context={}
         server_id = context.get('server_id',False)
         server_type = context.get('server_type',False)
diff --git a/addons/google_map/wizard/google_map_launch.py b/addons/google_map/wizard/google_map_launch.py
index 6ae9c19d2ce..a2b3003da7c 100644
--- a/addons/google_map/wizard/google_map_launch.py
+++ b/addons/google_map/wizard/google_map_launch.py
@@ -26,8 +26,6 @@ from osv import fields
 import time
 
 def _launch_wizard(self, cr, uid, data, context=None):
-    if not context:
-        context = {}
     address_obj= pooler.get_pool(cr.dbname).get('res.partner.address')
     m= address_obj.browse(cr, uid, data['id'], context=context)
     url=''
diff --git a/addons/hr/hr.py b/addons/hr/hr.py
index d8dfe2907ad..b1742a0f87c 100644
--- a/addons/hr/hr.py
+++ b/addons/hr/hr.py
@@ -28,8 +28,6 @@ class hr_employee_category(osv.osv):
     def name_get(self, cr, uid, ids, context=None):
         if not ids:
             return []
-        if not context:
-            context = {}
         reads = self.read(cr, uid, ids, ['name','parent_id'], context=context)
         res = []
         for record in reads:
@@ -40,8 +38,6 @@ class hr_employee_category(osv.osv):
         return res
 
     def _name_get_fnc(self, cr, uid, ids, prop, unknow_none, context=None):
-        if not context:
-            context = {}
         res = self.name_get(cr, uid, ids, context=context)
         return dict(res)
 
@@ -55,8 +51,6 @@ class hr_employee_category(osv.osv):
     }
 
     def _check_recursion(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         level = 100
         while len(ids):
             cr.execute('select distinct parent_id from hr_employee_category where id IN %s', (tuple(ids), ))
@@ -86,16 +80,12 @@ class hr_job(osv.osv):
 
     def _no_of_employee(self, cr, uid, ids, name, args, context=None):
         res = {}
-        if not context:
-            context = {}
         for job in self.browse(cr, uid, ids, context=context):
             res[job.id] = len(job.employee_ids or [])
         return res
 
     def _no_of_recruitement(self, cr, uid, ids, name, args, context=None):
         res = {}
-        if not context:
-            context = {}
         for job in self.browse(cr, uid, ids, context=context):
             res[job.id] = job.expected_employees - job.no_of_employee
         return res
@@ -175,8 +165,6 @@ class hr_employee(osv.osv):
 
     def onchange_company(self, cr, uid, ids, company, context=None):
         address_id = False
-        if not context:
-            context = {}
         if company:
             company_id = self.pool.get('res.company').browse(cr, uid, company, context=context)
             address = self.pool.get('res.partner').address_get(cr, uid, [company_id.partner_id.id], ['default'])
@@ -185,8 +173,6 @@ class hr_employee(osv.osv):
 
     def onchange_user(self, cr, uid, ids, user_id, context=None):
         work_email = False
-        if not context:
-            context = {}
         if user_id:
             work_email = self.pool.get('res.users').browse(cr, uid, user_id, context=context).user_email
         return {'value': {'work_email' : work_email}}
@@ -203,8 +189,6 @@ class hr_employee(osv.osv):
 
     def _check_recursion(self, cr, uid, ids, context=None):
         level = 100
-        if not context:
-            context = {}
         while len(ids):
             cr.execute('SELECT DISTINCT parent_id FROM hr_employee WHERE id IN %s AND parent_id!=id',(tuple(ids),))
             ids = filter(None, map(lambda x:x[0], cr.fetchall()))
@@ -214,8 +198,6 @@ class hr_employee(osv.osv):
         return True
 
     def _check_department_id(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for emp in self.browse(cr, uid, ids, context=context):
             if emp.department_id.manager_id and emp.id == emp.department_id.manager_id.id:
                 return False
diff --git a/addons/hr_contract/hr_contract.py b/addons/hr_contract/hr_contract.py
index 51d83cd33cd..3ad44ef3065 100644
--- a/addons/hr_contract/hr_contract.py
+++ b/addons/hr_contract/hr_contract.py
@@ -29,8 +29,6 @@ class hr_employee(osv.osv):
 
     def _get_latest_contract(self, cr, uid, ids, field_name, args, context=None):
         res = {}
-        if not context:
-            context = {}
         obj_contract = self.pool.get('hr.contract')
         for emp in self.browse(cr, uid, ids, context=context):
             contract_ids = obj_contract.search(cr, uid, [('employee_id','=',emp.id),], order='date_start', context=context)
diff --git a/addons/hr_evaluation/hr_evaluation.py b/addons/hr_evaluation/hr_evaluation.py
index 2d4a8948265..4e635f5f594 100644
--- a/addons/hr_evaluation/hr_evaluation.py
+++ b/addons/hr_evaluation/hr_evaluation.py
@@ -371,7 +371,7 @@ class hr_evaluation_interview(osv.osv):
         @param context: A standard dictionary for contextual values
         @return: Dictionary value for print survey form.
         """
-        if not context:
+        if context is None:
             context = {}
         record = self.browse(cr, uid, ids, context=context)
         record = record and record[0]
diff --git a/addons/hr_expense/hr_expense.py b/addons/hr_expense/hr_expense.py
index aa98d1d0c98..638d6eb19fb 100644
--- a/addons/hr_expense/hr_expense.py
+++ b/addons/hr_expense/hr_expense.py
@@ -100,8 +100,6 @@ class hr_expense_expense(osv.osv):
 
     def onchange_employee_id(self, cr, uid, ids, employee_id, context=None):
         department_id = False
-        if not context:
-            context = {}
         if employee_id:
             department_id = self.pool.get('hr.employee').browse(cr, uid, employee_id, context=context).department_id.id or False
         return {'value':{'department_id':department_id}}
diff --git a/addons/hr_payroll/hr_payroll.py b/addons/hr_payroll/hr_payroll.py
index e6e750acfa8..69b2b0f33aa 100644
--- a/addons/hr_payroll/hr_payroll.py
+++ b/addons/hr_payroll/hr_payroll.py
@@ -133,7 +133,7 @@ class hr_contract(osv.osv):
 
     def compute_basic(self, cr, uid, ids, context=None):
         res = {}
-        if not context:
+        if context is None:
             context = {}
         ids += context.get('employee_structure', [])
 
@@ -248,8 +248,6 @@ class hr_contract(osv.osv):
         return False
 
     def _calculate_salary(self, cr, uid, ids, field_names, arg, context=None):
-        if not context:
-            context = {}
         res = self.compute_basic(cr, uid, ids, context=context)
         vals = {}
         for rs in self.browse(cr, uid, ids, context=context):
@@ -346,8 +344,6 @@ class payroll_register(osv.osv):
         deduction = 0.0
         net = 0.0
         grows = 0.0
-        if not context:
-            context = {}
         for register in self.browse(cr, uid, ids, context=context):
             for slip in register.line_ids:
                 allounce += slip.allounce
@@ -614,8 +610,6 @@ class contrib_register(osv.osv):
     _description = 'Contribution Register'
 
     def _total_contrib(self, cr, uid, ids, field_names, arg, context=None):
-        if not context:
-            context = {}
         line_pool = self.pool.get('hr.contibution.register.line')
 
         res = {}
@@ -782,8 +776,6 @@ class company_contribution(osv.osv):
         return res
 
     def compute(self, cr, uid, id, value, context=None):
-        if not context:
-            context = {}
         contrib = self.browse(cr, uid, id, context=context)
         if contrib.amount_type == 'fix':
             return contrib.contribute_per
@@ -1001,8 +993,6 @@ class hr_payslip(osv.osv):
         return True
 
     def verify_sheet(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         register_pool = self.pool.get('company.contribution')
         register_line_pool = self.pool.get('hr.contibution.register.line')
 
@@ -1437,8 +1427,6 @@ class hr_employee(osv.osv):
 
     def _calculate_salary(self, cr, uid, ids, field_names, arg, context=None):
         vals = {}
-        if not context:
-            context = {}
         slip_line_pool = self.pool.get('hr.payslip.line')
 
         for employee in self.browse(cr, uid, ids, context=context):
diff --git a/addons/hr_payroll_account/hr_payroll_account.py b/addons/hr_payroll_account/hr_payroll_account.py
index 7d147ce4d66..a3b3cd72b9b 100644
--- a/addons/hr_payroll_account/hr_payroll_account.py
+++ b/addons/hr_payroll_account/hr_payroll_account.py
@@ -110,8 +110,6 @@ class payroll_register(osv.osv):
         func_pool = self.pool.get('hr.payroll.structure')
         slip_line_pool = self.pool.get('hr.payslip.line')
         wf_service = netsvc.LocalService("workflow")
-        if not context:
-            context = {}
         vals = self.browse(cr, uid, ids, context=context)[0]
         emp_ids = emp_pool.search(cr, uid, [])
 
diff --git a/addons/hr_recruitment/hr_recruitment.py b/addons/hr_recruitment/hr_recruitment.py
index 900a15806e1..bc38e9444ee 100644
--- a/addons/hr_recruitment/hr_recruitment.py
+++ b/addons/hr_recruitment/hr_recruitment.py
@@ -200,8 +200,6 @@ class hr_applicant(crm.crm_case, osv.osv):
         @param ids: List of case IDs
         @param context: A standard dictionary for contextual values"""
         stage_obj = self.pool.get('hr.recruitment.stage')
-        if not context:
-            context = {}
         for case in self.browse(cr, uid, ids, context=context):
             department = (case.department_id.id or False)
             st = case.stage_id.id  or False
@@ -219,8 +217,6 @@ class hr_applicant(crm.crm_case, osv.osv):
         @param ids: List of case IDs
         @param context: A standard dictionary for contextual values"""
         stage_obj = self.pool.get('hr.recruitment.stage')
-        if not context:
-            context = {}
         for case in self.browse(cr, uid, ids, context=context):
             department = (case.department_id.id or False)
             st = case.stage_id.id  or False
@@ -291,7 +287,7 @@ class hr_applicant(crm.crm_case, osv.osv):
         @param context: A standard dictionary for contextual values
         @return: Dictionary value for print survey form.
         """
-        if not context:
+        if context is None:
             context = {}
         record = self.browse(cr, uid, ids, context=context)
         record = record and record[0]
diff --git a/addons/hr_timesheet_sheet/hr_timesheet_sheet.py b/addons/hr_timesheet_sheet/hr_timesheet_sheet.py
index e36ed2a5e0b..ddaba6ebdf9 100644
--- a/addons/hr_timesheet_sheet/hr_timesheet_sheet.py
+++ b/addons/hr_timesheet_sheet/hr_timesheet_sheet.py
@@ -349,8 +349,6 @@ class hr_timesheet_sheet(osv.osv):
     }
 
     def _sheet_date(self, cr, uid, ids, forced_user_id=False, context=None):
-        if not context:
-            context = {}
         for sheet in self.browse(cr, uid, ids, context=context):
             new_user_id = forced_user_id or sheet.user_id and sheet.user_id.id
             if new_user_id:
@@ -364,8 +362,6 @@ class hr_timesheet_sheet(osv.osv):
         return True
 
     def _date_current_check(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for sheet in self.browse(cr, uid, ids, context=context):
             if sheet.date_current < sheet.date_from or sheet.date_current > sheet.date_to:
                 return False
diff --git a/addons/idea/idea.py b/addons/idea/idea.py
index 3cabb9ad4cc..deda3ab1350 100644
--- a/addons/idea/idea.py
+++ b/addons/idea/idea.py
@@ -121,8 +121,6 @@ class idea_idea(osv.osv):
         @param ids: List of vote read’s IDs """
 
         res = {}
-        if not context:
-            context = {}
         for id in ids:
             res[id] = '-1'
         vote_obj = self.pool.get('idea.vote')
@@ -248,8 +246,6 @@ class idea_idea(osv.osv):
 
         @return: Returns True on success, False otherwise
         """
-        if not context:
-            context = {}
         state = self.browse(cr, user, ids[0], context=context).state
 
         if vals.get('my_vote', False):
diff --git a/addons/idea/wizard/idea_post_vote.py b/addons/idea/wizard/idea_post_vote.py
index 540796c0d9e..a4f179eedbb 100644
--- a/addons/idea/wizard/idea_post_vote.py
+++ b/addons/idea/wizard/idea_post_vote.py
@@ -48,7 +48,7 @@ class idea_post_vote(osv.osv_memory):
         @param fields: List of fields for default value
         @param context: A standard dictionary for contextual values
         """
-        if not context:
+        if context is None:
             context = {}
         idea_obj = self.pool.get('idea.idea')
 
@@ -149,7 +149,7 @@ class idea_select(osv.osv_memory):
        @param ids: List of load column,
        @return: dictionary of query logs clear message window
        """
-       if not context:
+       if context is None:
             context = {}
        idea_obj = self.browse(cr, uid, ids, context=context)
        for idea in idea_obj:
diff --git a/addons/l10n_ch/wizard/create_dta.py b/addons/l10n_ch/wizard/create_dta.py
index 94c623af13d..cf87b88024b 100644
--- a/addons/l10n_ch/wizard/create_dta.py
+++ b/addons/l10n_ch/wizard/create_dta.py
@@ -581,7 +581,7 @@ class create_dta_wizard(osv.osv_memory):
         'dta_file':fields.binary('DTA File', readonly=True)
     }
     def create_dta(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         data = {}
         active_ids = context.get('active_ids', [])
diff --git a/addons/lunch/lunch.py b/addons/lunch/lunch.py
index c1f4b539bdb..1499dd4414e 100644
--- a/addons/lunch/lunch.py
+++ b/addons/lunch/lunch.py
@@ -72,8 +72,6 @@ class lunch_cashbox(osv.osv):
         @param ids: List of create menu’s IDs
         @param context: A standard dictionary for contextual values """
 
-        if not context:
-            context = {}
         cr.execute("SELECT box,sum(amount) from lunch_cashmove where active = 't' group by box")
         amount = dict(cr.fetchall())
         for i in ids:
@@ -126,8 +124,6 @@ class lunch_order(osv.osv):
          @param ids: List of Lunch order’s IDs
          @param context: A standard dictionary for contextual values """
 
-        if not context:
-            context = {}
         res = {}
         for price in self.browse(cr, uid, ids, context=context):
             res[price.id] = price.product.price
@@ -162,8 +158,6 @@ class lunch_order(osv.osv):
         @param ids: List of confirm order’s IDs
         @param context: A standard dictionary for contextual values """
 
-        if not context:
-            context = {}
         cashmove_ref = self.pool.get('lunch.cashmove')
         for order in self.browse(cr, uid, ids, context=context):
             if order.state == 'confirmed':
@@ -185,8 +179,6 @@ class lunch_order(osv.osv):
          @param ids: List of create menu’s IDs
          @param context: A standard dictionary for contextual values """
 
-        if not context:
-            context = {}
         orders = self.browse(cr, uid, ids, context=context)
         for order in orders:
             if not order.cashmove:
diff --git a/addons/lunch/wizard/lunch_cashbox_clean.py b/addons/lunch/wizard/lunch_cashbox_clean.py
index f964854d677..9c03173fd0e 100644
--- a/addons/lunch/wizard/lunch_cashbox_clean.py
+++ b/addons/lunch/wizard/lunch_cashbox_clean.py
@@ -36,7 +36,7 @@ class lunch_cashbox_clean(osv.osv_memory):
          @return:Dictionary {}.
          """
          #TOFIX: use orm methods
-         if not context:
+         if context is None:
             context = {}
          data = context and context.get('active_ids', []) or []
          cashmove_ref = self.pool.get('lunch.cashmove')
diff --git a/addons/lunch/wizard/lunch_order_cancel.py b/addons/lunch/wizard/lunch_order_cancel.py
index 9e3185fdca4..a0c8779b323 100644
--- a/addons/lunch/wizard/lunch_order_cancel.py
+++ b/addons/lunch/wizard/lunch_order_cancel.py
@@ -34,7 +34,7 @@ class lunch_order_cancel(osv.osv_memory):
         @param uid: the current user’s ID for security checks,
         @param ids: List  Lunch Order Cancel’s IDs
         """
-        if not context:
+        if context is None:
             context = {}
         data = context and context.get('active_ids', []) or []
         return self.pool.get('lunch.order').lunch_order_cancel(cr, uid, data, context)
diff --git a/addons/lunch/wizard/lunch_order_confirm.py b/addons/lunch/wizard/lunch_order_confirm.py
index ed0037fc980..4a9ba66ce9f 100644
--- a/addons/lunch/wizard/lunch_order_confirm.py
+++ b/addons/lunch/wizard/lunch_order_confirm.py
@@ -41,7 +41,7 @@ class lunch_order_confirm(osv.osv_memory):
         @param ids: List  Lunch Order confirm’s IDs
         @return: Dictionary {}.
         """
-        if not context:
+        if context is None:
             context = {}
         data = context and context.get('active_ids', []) or []
         order_ref = self.pool.get('lunch.order')
diff --git a/addons/mail_gateway/mail_gateway.py b/addons/mail_gateway/mail_gateway.py
index cce1f2685f3..a5d48956b1a 100644
--- a/addons/mail_gateway/mail_gateway.py
+++ b/addons/mail_gateway/mail_gateway.py
@@ -76,8 +76,6 @@ class mailgate_thread(osv.osv):
         """ Get a list of emails of the people following this thread
         """
         res = {}
-        if not context:
-            context = {}
         if isinstance(ids, (str, int, long)):
             ids = [long(ids)]
         for thread in self.browse(cr, uid, ids, context=context):
@@ -190,8 +188,6 @@ class mailgate_message(osv.osv):
         @param context: A standard dictionary
         """
         action_data = False
-        if not context:
-            context = {}
         if ids:
             message_id = ids[0]
             mailgate_data = self.browse(cr, uid, message_id, context=context)
@@ -217,8 +213,6 @@ class mailgate_message(osv.osv):
         @param context: A standard dictionary
         """
         action_data = False
-        if not context:
-            context = {}
         action_pool = self.pool.get('ir.actions.act_window')
         message_pool = self.browse(cr ,uid, ids, context=context)[0]
         action_ids = action_pool.search(cr, uid, [('res_model', '=', 'ir.attachment')])
@@ -323,8 +317,6 @@ class mailgate_tool(osv.osv_memory):
         """
         if isinstance(res_ids, (int, long)):
             res_ids = [res_ids]
-        if not context:
-            context = {}
 
         msg_pool = self.pool.get('mailgate.message')
         for res_id in res_ids:
@@ -358,8 +350,6 @@ class mailgate_tool(osv.osv_memory):
         @param email_error: Default Email address in case of any Problem
         """
         model_pool = self.pool.get(model)
-        if not context:
-            context = {}
 
         for res in model_pool.browse(cr, uid, res_ids, context=context):
             message_followers = model_pool.message_followers(cr, uid, [res.id])[res.id]
@@ -400,7 +390,7 @@ class mailgate_tool(osv.osv_memory):
         if isinstance(message, xmlrpclib.Binary):
             message = str(message.data)
 
-        if not context:
+        if context is None:
             context = {}
 
         if custom_values is None or not isinstance(custom_values, dict):
diff --git a/addons/marketing_campaign/marketing_campaign.py b/addons/marketing_campaign/marketing_campaign.py
index 7144f401034..bd2a63e06ec 100644
--- a/addons/marketing_campaign/marketing_campaign.py
+++ b/addons/marketing_campaign/marketing_campaign.py
@@ -167,8 +167,6 @@ Normal - the campaign runs normally and automatically sends all emails and repor
     def _signal(self, cr, uid, record, signal, run_existing=True, context=None):
         if not signal:
             raise ValueError('signal cannot be False')
-        if not context:
-            context = {}
 
         Workitems = self.pool.get('marketing.campaign.workitem')
         domain = [('object_id.model', '=', record._table._name),
@@ -249,8 +247,6 @@ class marketing_campaign_segment(osv.osv):
     }
 
     def _check_model(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for obj in self.browse(cr, uid, ids, context=context):
             if not obj.ir_filter_id:
                 return True
@@ -302,8 +298,6 @@ class marketing_campaign_segment(osv.osv):
         return True
 
     def process_segment(self, cr, uid, segment_ids=None, context=None):
-        if not context:
-            context = {}
         Workitems = self.pool.get('marketing.campaign.workitem')
         if not segment_ids:
             segment_ids = self.search(cr, uid, [('state', '=', 'running')], context=context)
@@ -466,8 +460,6 @@ class marketing_campaign_activity(osv.osv):
         return res == False and True or res
 
     def process(self, cr, uid, act_id, wi_id, context=None):
-        if not context:
-            context = {}
         activity = self.browse(cr, uid, act_id, context=context)
         method = '_process_wi_%s' % (activity.type,)
         action = getattr(self, method, None)
@@ -504,8 +496,6 @@ class marketing_campaign_transition(osv.osv):
 
     def _delta(self, cr, uid, ids, context=None):
         assert len(ids) == 1
-        if not context:
-            context = {}
         transition = self.browse(cr, uid, ids[0], context=context)
         if transition.trigger != 'time':
             raise ValueError('Delta is only relevant for timed transiton')
@@ -539,8 +529,6 @@ class marketing_campaign_transition(osv.osv):
         'trigger': 'time',
     }
     def _check_campaign(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for obj in self.browse(cr, uid, ids, context=context):
             if obj.activity_from_id.campaign_id != obj.activity_to_id.campaign_id:
                 return False
@@ -562,8 +550,6 @@ class marketing_campaign_workitem(osv.osv):
 
     def _res_name_get(self, cr, uid, ids, field_name, arg, context=None):
         res = dict.fromkeys(ids, '/')
-        if not context:
-            context = {}
         for wi in self.browse(cr, uid, ids, context=context):
             if not wi.res_id:
                 continue
@@ -625,16 +611,12 @@ class marketing_campaign_workitem(osv.osv):
     }
 
     def button_draft(self, cr, uid, workitem_ids, context=None):
-        if not context:
-            context = {}
         for wi in self.browse(cr, uid, workitem_ids, context=context):
             if wi.state in ('exception', 'cancelled'):
                 self.write(cr, uid, [wi.id], {'state':'todo'}, context=context)
         return True
 
     def button_cancel(self, cr, uid, workitem_ids, context=None):
-        if not context:
-            context = {}
         for wi in self.browse(cr, uid, workitem_ids, context=context):
             if wi.state in ('todo','exception'):
                 self.write(cr, uid, [wi.id], {'state':'cancelled'}, context=context)
@@ -644,8 +626,6 @@ class marketing_campaign_workitem(osv.osv):
         if workitem.state != 'todo':
             return
 
-        if not context:
-            context = {}
         activity = workitem.activity_id
         proxy = self.pool.get(workitem.object_id.model)
         object_id = proxy.browse(cr, uid, workitem.res_id, context=context)
@@ -756,8 +736,6 @@ class marketing_campaign_workitem(osv.osv):
 
     def preview(self, cr, uid, ids, context=None):
         res = {}
-        if not context:
-            context = {}
         wi_obj = self.browse(cr, uid, ids[0], context=context)
         if wi_obj.activity_id.type == 'email':
             data_obj = self.pool.get('ir.model.data')
diff --git a/addons/membership/membership.py b/addons/membership/membership.py
index e34e7e2849b..5f9a9e6ee66 100644
--- a/addons/membership/membership.py
+++ b/addons/membership/membership.py
@@ -50,8 +50,6 @@ class membership_line(osv.osv):
 
     def _get_partners(self, cr, uid, ids, context=None):
         list_membership_line = []
-        if not context:
-            context = {}
         member_line_obj = self.pool.get('membership.membership_line')
         for partner in self.pool.get('res.partner').browse(cr, uid, ids, context=context):
             if partner.member_lines:
@@ -60,8 +58,6 @@ class membership_line(osv.osv):
 
     def _get_membership_lines(self, cr, uid, ids, context=None):
         list_membership_line = []
-        if not context:
-            context = {}
         member_line_obj = self.pool.get('membership.membership_line')
         for invoice in self.pool.get('account.invoice').browse(cr, uid, ids, context=context):
             if invoice.invoice_line:
@@ -103,8 +99,6 @@ class membership_line(osv.osv):
         @param return: Dictionary of state Value
         """
         res = {}
-        if not context:
-            context = {}
         inv_obj = self.pool.get('account.invoice')
         for line in self.browse(cr, uid, ids, context=context):
             cr.execute('''
@@ -185,8 +179,6 @@ class Partner(osv.osv):
     def _get_partner_id(self, cr, uid, ids, context=None):
         member_line_obj = self.pool.get('membership.membership_line')
         res_obj =  self.pool.get('res.partner')
-        if not context:
-            context = {}
         data_inv = member_line_obj.browse(cr, uid, ids, context=context)
         list_partner = []
         for data in data_inv:
@@ -200,8 +192,6 @@ class Partner(osv.osv):
     def _get_invoice_partner(self, cr, uid, ids, context=None):
         inv_obj = self.pool.get('account.invoice')
         res_obj = self.pool.get('res.partner')
-        if not context:
-            context = {}
         data_inv = inv_obj.browse(cr, uid, ids, context=context)
         list_partner = []
         for data in data_inv:
@@ -226,8 +216,6 @@ class Partner(osv.osv):
         for id in ids:
             res[id] = 'none'
         today = time.strftime('%Y-%m-%d')
-        if not context:
-            context = {}
         for id in ids:
             partner_data = self.browse(cr, uid, id, context=context)
             if partner_data.membership_cancel and today > partner_data.membership_cancel:
@@ -285,8 +273,6 @@ class Partner(osv.osv):
         name = name[0]
         res = {}
         member_line_obj = self.pool.get('membership.membership_line')
-        if not context:
-            context = {}
         for partner in self.browse(cr, uid, ids, context=context):
             if partner.associate_member:
                  partner_id = partner.associate_member.id
@@ -320,8 +306,6 @@ class Partner(osv.osv):
 
     def _get_partners(self, cr, uid, ids, context=None):
         ids2 = ids
-        if not context:
-            context = {}
         while ids2:
             ids2 = self.search(cr, uid, [('associate_member', 'in', ids2)], context=context)
             ids += ids2
@@ -386,8 +370,6 @@ class Partner(osv.osv):
         """Check  Recursive  for Associated Members.
         """
         level = 100
-        if not context:
-            context = {}
         while len(ids):
             cr.execute('SELECT DISTINCT associate_member FROM res_partner WHERE id IN %s', (tuple(ids),))
             ids = filter(None, map(lambda x:x[0], cr.fetchall()))
@@ -419,7 +401,7 @@ class Partner(osv.osv):
         invoice_tax_obj = self.pool.get('account.invoice.tax')
         product_id = product_id or datas.get('membership_product_id', False)
         amount = datas.get('amount', 0.0)
-        if not context:
+        if context is None:
             context={}
         invoice_list = []
         if type(ids) in (int, long,):
@@ -478,7 +460,7 @@ class Product(osv.osv):
 
     def fields_view_get(self, cr, user, view_id=None, view_type='form', context=None, toolbar=False, submenu=False):
         model_obj = self.pool.get('ir.model.data')
-        if not context:
+        if context is None:
             context = {}
 
         if ('product' in context) and (context['product']=='membership_product'):
@@ -531,7 +513,7 @@ class account_invoice_line(osv.osv):
     def write(self, cr, uid, ids, vals, context=None):
         """Overrides orm write method
         """
-        if not context:
+        if context is None:
             context={}
         member_line_obj = self.pool.get('membership.membership_line')
         res = super(account_invoice_line, self).write(cr, uid, ids, vals, context=context)
@@ -561,7 +543,7 @@ class account_invoice_line(osv.osv):
     def unlink(self, cr, uid, ids, context=None):
         """Remove Membership Line Record for Account Invoice Line
         """
-        if not context:
+        if context is None:
             context={}
         member_line_obj = self.pool.get('membership.membership_line')
         for id in ids:
diff --git a/addons/membership/wizard/membership_invoice.py b/addons/membership/wizard/membership_invoice.py
index 670e3470eb2..b97926e564c 100644
--- a/addons/membership/wizard/membership_invoice.py
+++ b/addons/membership/wizard/membership_invoice.py
@@ -42,7 +42,7 @@ class membership_invoice(osv.osv_memory):
         mod_obj = self.pool.get('ir.model.data')
         partner_obj = self.pool.get('res.partner')
         datas = {}
-        if not context:
+        if context is None:
             context = {}
         data = self.browse(cr, uid, ids, context=context)
         if data:
diff --git a/addons/mrp/mrp.py b/addons/mrp/mrp.py
index 0338d6ff242..88ac6a5e266 100644
--- a/addons/mrp/mrp.py
+++ b/addons/mrp/mrp.py
@@ -132,7 +132,7 @@ class mrp_bom(osv.osv):
         @return:  Dictionary of values
         """
         result = {}
-        if not context:
+        if context is None:
             context = {}
         bom_obj = self.pool.get('mrp.bom')
         bom_id = context and context.get('active_id', False) or False
@@ -164,8 +164,6 @@ class mrp_bom(osv.osv):
         @return:  Dictionary of values
         """
         res = dict(map(lambda x: (x,''), ids))
-        if not context:
-            context = {}
         for line in self.browse(cr, uid, ids, context=context):
             if line.type == 'phantom' and not line.bom_id:
                 res[line.id] = 'set'
@@ -223,8 +221,6 @@ class mrp_bom(osv.osv):
 
     def _check_recursion(self, cr, uid, ids, context=None):
         level = 100
-        if not context:
-            context = {}
         while len(ids):
             cr.execute('select distinct bom_id from mrp_bom where id IN %s',(tuple(ids),))
             ids = filter(None, map(lambda x:x[0], cr.fetchall()))
@@ -370,8 +366,6 @@ class mrp_production(osv.osv):
         @return: Dictionary of values.
         """
         result = {}
-        if not context:
-            context = {}
         for prod in self.browse(cr, uid, ids, context=context):
             result[prod.id] = {
                 'hour_total': 0.0,
@@ -389,8 +383,6 @@ class mrp_production(osv.osv):
         @return: Dictionary of values.
         """
         result = {}
-        if not context:
-            context = {}
         for prod in self.browse(cr, uid, ids, context=context):
             result[prod.id] = prod.date_planned
         return result
@@ -402,8 +394,6 @@ class mrp_production(osv.osv):
         @return: Dictionary of values.
         """
         result = {}
-        if not context:
-            context = {}
         for prod in self.browse(cr, uid, ids, context=context):
             result[prod.id] = prod.date_planned[:10]
         return result
@@ -460,8 +450,6 @@ class mrp_production(osv.osv):
     _order = 'priority desc, date_planned asc';
     
     def _check_qty(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         orders = self.browse(cr, uid, ids, context=context)
         for order in orders:
             if order.product_qty <= 0:
@@ -519,8 +507,6 @@ class mrp_production(osv.osv):
                 'bom_id': False,
                 'routing_id': False
             }}
-        if not context:
-            context = {}
         bom_obj = self.pool.get('mrp.bom')
         product = self.pool.get('product.product').browse(cr, uid, product_id, context=context)
         bom_id = bom_obj._bom_find(cr, uid, product.id, product.uom_id and product.uom_id.id, [])
@@ -544,8 +530,6 @@ class mrp_production(osv.osv):
             return {'value': {
                 'routing_id': False
             }}
-        if not context:
-            context = {}
         bom_pool = self.pool.get('mrp.bom')
         bom_point = bom_pool.browse(cr, uid, bom_id, context=context)
         routing_id = bom_point.routing_id.id or False
@@ -657,7 +641,7 @@ class mrp_production(osv.osv):
         @param production_mode: specify production mode (consume/consume&produce).
         @return: True
         """
-        if not context:
+        if context is None:
             context = {}
         stock_mov_obj = self.pool.get('stock.move')
         production = self.browse(cr, uid, production_id, context=context)
diff --git a/addons/mrp/procurement.py b/addons/mrp/procurement.py
index 947169afa7c..b19c2c0e15e 100644
--- a/addons/mrp/procurement.py
+++ b/addons/mrp/procurement.py
@@ -50,8 +50,6 @@ class procurement_order(osv.osv):
         return True
     
     def get_phantom_bom_id(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for procurement in self.browse(cr, uid, ids, context=context):
             if procurement.move_id and procurement.move_id.product_id.supply_method=='produce' \
                  and procurement.move_id.product_id.procure_method=='make_to_order':
@@ -66,8 +64,6 @@ class procurement_order(osv.osv):
         """ This is action which call from workflow to assign production order to procurements
         @return: True
         """
-        if not context:
-            context = {}
         procurement_obj = self.pool.get('procurement.order')
         res = procurement_obj.make_mo(cr, uid, ids, context=context)
         res = res.values()
@@ -78,14 +74,12 @@ class procurement_order(osv.osv):
         @return: New created Production Orders procurement wise 
         """
         res = {}
-        if not context:
-            context = {}
         company = self.pool.get('res.users').browse(cr, uid, uid, context).company_id
         production_obj = self.pool.get('mrp.production')
         move_obj = self.pool.get('stock.move')
         wf_service = netsvc.LocalService("workflow")
         procurement_obj = self.pool.get('procurement.order')
-        for procurement in procurement_obj.browse(cr, uid, ids):
+        for procurement in procurement_obj.browse(cr, uid, ids, context=context):
             res_id = procurement.move_id.id
             loc_id = procurement.location_id.id
             newdate = datetime.strptime(procurement.date_planned, '%Y-%m-%d %H:%M:%S') - relativedelta(days=procurement.product_id.product_tmpl_id.produce_delay or 0.0)
diff --git a/addons/mrp/product.py b/addons/mrp/product.py
index 29ecb3bec01..bb9bc27625f 100644
--- a/addons/mrp/product.py
+++ b/addons/mrp/product.py
@@ -31,8 +31,6 @@ class product_product(osv.osv):
         @param product_id: product id            
         @return: dictionary which contains information regarding stock input account, stock output account and stock journal
         """
-        if not context:
-            context = {}           
         product_obj = self.pool.get('product.product').browse(cr, uid, product_id, False)
         res = super(product_product,self).get_product_accounts(cr, uid, product_id, context=context)
         stock_input_acc = product_obj.property_stock_account_input and product_obj.property_stock_account_input.id or False 
@@ -62,7 +60,7 @@ class product_product(osv.osv):
         @param context: A standard dictionary
         @return:
         """
-        if not context:
+        if context is None:
             context = {}
         res = super(product_product, self).do_change_standard_price(cr, uid, ids, datas, context=context)
         bom_obj = self.pool.get('mrp.bom')
diff --git a/addons/mrp/stock.py b/addons/mrp/stock.py
index f1493dffb25..3e50552cd9e 100644
--- a/addons/mrp/stock.py
+++ b/addons/mrp/stock.py
@@ -41,8 +41,6 @@ class StockMove(osv.osv):
         procurement_obj = self.pool.get('procurement.order')
         product_obj = self.pool.get('product.product')
         wf_service = netsvc.LocalService("workflow")
-        if not context:
-            context = {}
         if move.product_id.supply_method == 'produce' and move.product_id.procure_method == 'make_to_order':
             bis = bom_obj.search(cr, uid, [
                 ('product_id','=',move.product_id.id),
@@ -126,8 +124,6 @@ class StockMove(osv.osv):
         @return: Scraped lines
         """  
         res = []
-        if not context:
-            context = {}
         production_obj = self.pool.get('mrp.production')
         wf_service = netsvc.LocalService("workflow")
         for move in self.browse(cr, uid, ids, context=context):
@@ -175,8 +171,6 @@ class spilt_in_production_lot(osv.osv_memory):
         production_obj = self.pool.get('mrp.production')
         move_obj = self.pool.get('stock.move')  
         res = []
-        if not context:
-            context = {}      
         for move in move_obj.browse(cr, uid, move_ids, context=context):
             new_moves = super(spilt_in_production_lot, self).split(cr, uid, ids, move_ids, context=context)
             production_ids = production_obj.search(cr, uid, [('move_lines', 'in', [move.id])])
diff --git a/addons/mrp/wizard/change_production_qty.py b/addons/mrp/wizard/change_production_qty.py
index 318da999caa..87b6d00190e 100644
--- a/addons/mrp/wizard/change_production_qty.py
+++ b/addons/mrp/wizard/change_production_qty.py
@@ -39,7 +39,7 @@ class change_production_qty(osv.osv_memory):
         @param context: A standard dictionary 
         @return: A dictionary which of fields with values. 
         """        
-        if not context:
+        if context is None:
             context = {}
         res = super(change_production_qty, self).default_get(cr, uid, fields, context=context)        
         prod_obj = self.pool.get('mrp.production')
diff --git a/addons/mrp/wizard/mrp_change_standard_price.py b/addons/mrp/wizard/mrp_change_standard_price.py
index a353e433598..4ee92aac16b 100644
--- a/addons/mrp/wizard/mrp_change_standard_price.py
+++ b/addons/mrp/wizard/mrp_change_standard_price.py
@@ -42,7 +42,7 @@ class change_standard_price(osv.osv_memory):
         @param context: A standard dictionary
         @return:
         """
-        if not context:
+        if context is None:
             context = {}
         res = self.browse(cr, uid, ids, context=context) 
         context.update({'change_parent_price': res[0].change_parent_price})
diff --git a/addons/mrp/wizard/mrp_price.py b/addons/mrp/wizard/mrp_price.py
index b57998f8c70..8e26561adad 100644
--- a/addons/mrp/wizard/mrp_price.py
+++ b/addons/mrp/wizard/mrp_price.py
@@ -39,7 +39,7 @@ class mrp_price(osv.osv_memory):
         @param context: A standard dictionary
         @return : Report
         """
-        if not context:
+        if context is None:
             context = {}
         datas = {'ids' : context.get('active_ids',[])}
         res = self.read(cr, uid, ids, ['number'])
diff --git a/addons/mrp/wizard/mrp_product_produce.py b/addons/mrp/wizard/mrp_product_produce.py
index a64329cbd0b..b1c06ad403d 100644
--- a/addons/mrp/wizard/mrp_product_produce.py
+++ b/addons/mrp/wizard/mrp_product_produce.py
@@ -42,7 +42,7 @@ class mrp_product_produce(osv.osv_memory):
         @param context: A standard dictionary
         @return: Quantity
         """
-        if not context:
+        if context is None:
             context = {}
         prod = self.pool.get('mrp.production').browse(cr, uid,
                                 context['active_id'], context=context)
@@ -66,7 +66,7 @@ class mrp_product_produce(osv.osv_memory):
         @param context: A standard dictionary
         @return:
         """
-        if not context:
+        if context is None:
             context = {}
         prod_obj = self.pool.get('mrp.production')
         move_ids = context.get('active_ids', [])
diff --git a/addons/mrp/wizard/mrp_track_prod.py b/addons/mrp/wizard/mrp_track_prod.py
index fb8374cf17c..4b883abf98c 100644
--- a/addons/mrp/wizard/mrp_track_prod.py
+++ b/addons/mrp/wizard/mrp_track_prod.py
@@ -54,7 +54,7 @@ class mrp_track_move(osv.osv_memory):
          @param context: A standard dictionary 
          @return: New arch of view.
         """
-        if not context:
+        if context is None:
             context = {}
         res = super(mrp_track_move, self).fields_view_get(cr, uid, view_id=view_id, view_type=view_type, context=context, toolbar=toolbar,submenu=False)
         record_id = context and context.get('active_id', False) or False
@@ -98,7 +98,7 @@ class mrp_track_move(osv.osv_memory):
          @param context: A standard dictionary 
          @return: 
         """
-        if not context:
+        if context is None:
             context = {}
         record_id = context and context.get('active_id', False) or False
         assert record_id, 'Active ID not found'
diff --git a/addons/mrp/wizard/mrp_workcenter_load.py b/addons/mrp/wizard/mrp_workcenter_load.py
index d7cd7f8f35a..fc4c90f8c54 100644
--- a/addons/mrp/wizard/mrp_workcenter_load.py
+++ b/addons/mrp/wizard/mrp_workcenter_load.py
@@ -38,7 +38,7 @@ class mrp_workcenter_load(osv.osv_memory):
         @param context: A standard dictionary
         @return : Report
         """
-        if not context:
+        if context is None:
             context = {}
         datas = {'ids' : context.get('active_ids',[])}
         res = self.read(cr, uid, ids, ['time_unit','measure_unit'])
diff --git a/addons/mrp_operations/mrp_operations.py b/addons/mrp_operations/mrp_operations.py
index 91589ad3bec..df5456baa4a 100644
--- a/addons/mrp_operations/mrp_operations.py
+++ b/addons/mrp_operations/mrp_operations.py
@@ -55,8 +55,6 @@ class mrp_production_workcenter_line(osv.osv):
         @return: Dictionary of values.
         """
         res={}
-        if not context:
-            context = {}
         for op in self.browse(cr, uid, ids, context=context):
             if op.date_start:
                 res[op.id] = op.date_start[:10]
@@ -68,8 +66,6 @@ class mrp_production_workcenter_line(osv.osv):
         """ Finds ending date.
         @return: Dictionary of values.
         """
-        if not context:
-            context = {}
         ops = self.browse(cr, uid, ids, context=context)
         date_and_hours_by_cal = [(op.date_planned, op.hour, op.workcenter_id.calendar_id.id) for op in ops if op.date_planned]
 
@@ -147,8 +143,6 @@ class mrp_production_workcenter_line(osv.osv):
         return
 
     def write(self, cr, uid, ids, vals, context=None, update=True):
-        if not context:
-            context = {}
         result = super(mrp_production_workcenter_line, self).write(cr, uid, ids, vals, context=context)
         prod_obj = self.pool.get('mrp.production')
         if vals.get('date_planned', False) and update:
@@ -224,8 +218,6 @@ class mrp_production(osv.osv):
         @return: Dictionary of values
         """
         result = {}
-        if not context:
-            context = {}
         for prod in self.browse(cr, uid, ids, context=context):
             result[prod.id] = prod.date_planned
             for line in prod.workcenter_lines:
@@ -267,7 +259,7 @@ class mrp_production(osv.osv):
         @return: Calculated date
         """
         dt_end = datetime.now()
-        if not context:
+        if context is None:
             context = {}
         for po in self.browse(cr, uid, ids, context=context):
             dt_end = datetime.strptime(po.date_planned, '%Y-%m-%d %H:%M:%S')
@@ -308,8 +300,6 @@ class mrp_production(osv.osv):
         """ Calculates start date for stock moves finding interval from resource calendar.
         @return: True 
         """
-        if not context:
-            context = {}
         for po in self.browse(cr, uid, ids, context=context):
             if po.allow_reorder:
                 continue
@@ -338,8 +328,6 @@ class mrp_production(osv.osv):
         """ Calculates start date for stock moves.
         @return: True 
         """
-        if not context:
-            context = {}
         for po in self.browse(cr, uid, ids, context=context):
             if po.allow_reorder:
                 continue
@@ -358,8 +346,6 @@ class mrp_production(osv.osv):
 
     def write(self, cr, uid, ids, vals, context=None, update=True, mini=True):
         direction = {}
-        if not context:
-            context = {}
         if vals.get('date_start', False):
             for po in self.browse(cr, uid, ids, context=context):
                 direction[po.id] = cmp(po.date_start, vals.get('date_start', False))
@@ -412,8 +398,6 @@ class mrp_operations_operation(osv.osv):
         @return: Dictionary of values
         """
         res={}
-        if not context:
-            context = {}
         operation_obj = self.browse(cr, uid, ids, context=context)
         for operation in operation_obj:
                 res[operation.id] = operation.production_id.date_planned
@@ -498,8 +482,6 @@ class mrp_operations_operation(osv.osv):
         return True
 
     def write(self, cr, uid, ids, vals, context=None):
-        if not context:
-            context = {}
         oper_objs = self.browse(cr, uid, ids, context=context)[0]
         vals['production_id']=oper_objs.production_id.id
         vals['workcenter_id']=oper_objs.workcenter_id.id
@@ -517,8 +499,6 @@ class mrp_operations_operation(osv.osv):
         return super(mrp_operations_operation, self).write(cr, uid, ids, vals, context=context)
 
     def create(self, cr, uid, vals, context=None):
-        if not context:
-            context = {}
         wf_service = netsvc.LocalService('workflow')
         code_ids=self.pool.get('mrp_operations.operation.code').search(cr,uid,[('id','=',vals['code_id'])])
         code=self.pool.get('mrp_operations.operation.code').browse(cr, uid, code_ids, context=context)[0]
diff --git a/addons/mrp_repair/mrp_repair.py b/addons/mrp_repair/mrp_repair.py
index 6de8b4f5492..dc51cd42b72 100644
--- a/addons/mrp_repair/mrp_repair.py
+++ b/addons/mrp_repair/mrp_repair.py
@@ -42,8 +42,6 @@ class mrp_repair(osv.osv):
         @return: Dictionary of values.
         """
         res = {}
-        if not context:
-            context = {}
         cur_obj = self.pool.get('res.currency')
 
         for repair in self.browse(cr, uid, ids, context=context):
@@ -66,8 +64,6 @@ class mrp_repair(osv.osv):
         #return {}.fromkeys(ids, 0)
         cur_obj = self.pool.get('res.currency')
         tax_obj = self.pool.get('account.tax')
-        if not context:
-            context = {}
         for repair in self.browse(cr, uid, ids, context=context):
             val = 0.0
             cur = repair.pricelist_id.currency_id
@@ -89,8 +85,6 @@ class mrp_repair(osv.osv):
         @return: Dictionary of values.
         """
         res = {}
-        if not context:
-            context = {}
         untax = self._amount_untaxed(cr, uid, ids, field_name, arg, context=context)
         tax = self._amount_tax(cr, uid, ids, field_name, arg, context=context)
         cur_obj = self.pool.get('res.currency')
@@ -102,8 +96,6 @@ class mrp_repair(osv.osv):
     
     def _get_default_address(self, cr, uid, ids, field_name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         partner_obj = self.pool.get('res.partner')
         for data in self.browse(cr, uid, ids, context=context):
             adr_id = False
@@ -192,8 +184,6 @@ class mrp_repair(osv.osv):
     def copy(self, cr, uid, id, default=None, context=None):
         if not default:
             default = {}
-        if not context:
-            context = {}
         default.update({
             'state':'draft',
             'repaired':False,
@@ -344,8 +334,6 @@ class mrp_repair(osv.osv):
         """ Cancels repair order.
         @return: True
         """
-        if not context:
-            context = {}
         mrp_line_obj = self.pool.get('mrp.repair.line')
         for repair in self.browse(cr, uid, ids, context=context):
             mrp_line_obj.write(cr, uid, [l.id for l in repair.operations], {'state': 'cancel'})
@@ -362,8 +350,6 @@ class mrp_repair(osv.osv):
         """
         res = {}
         invoices_group = {}
-        if not context:
-            context = {}
         inv_line_obj = self.pool.get('account.invoice.line')
         inv_obj = self.pool.get('account.invoice')
         repair_line_obj = self.pool.get('mrp.repair.line')
@@ -523,8 +509,6 @@ class mrp_repair(osv.osv):
         @return: Picking ids.
         """
         res = {}
-        if not context:
-            context = {}
         move_obj = self.pool.get('stock.move')
         wf_service = netsvc.LocalService("workflow")
         repair_line_obj = self.pool.get('mrp.repair.line')
@@ -648,8 +632,6 @@ class mrp_repair_line(osv.osv, ProductChangeMixin):
         @return: Dictionary of values.
         """
         res = {}
-        if not context:
-            context = {}
         cur_obj=self.pool.get('res.currency')
         for line in self.browse(cr, uid, ids, context=context):
             res[line.id] = line.to_invoice and line.price_unit * line.product_uom_qty or 0
@@ -739,8 +721,6 @@ class mrp_repair_fee(osv.osv, ProductChangeMixin):
         @return: Dictionary of values.
         """
         res = {}
-        if not context:
-            context = {}
         cur_obj = self.pool.get('res.currency')
         for line in self.browse(cr, uid, ids, context=context):
             res[line.id] = line.to_invoice and line.price_unit * line.product_uom_qty or 0
diff --git a/addons/mrp_repair/wizard/cancel_repair.py b/addons/mrp_repair/wizard/cancel_repair.py
index 7e081919660..e7ef69c2dcc 100644
--- a/addons/mrp_repair/wizard/cancel_repair.py
+++ b/addons/mrp_repair/wizard/cancel_repair.py
@@ -35,7 +35,7 @@ class repair_cancel(osv.osv_memory):
         @param context: A standard dictionary 
         @return:  
         """
-        if not context:
+        if context is None:
             context = {}
         record_id = context and context.get('active_id', False) or False
         assert record_id, _('Active ID is not Found')
@@ -58,7 +58,7 @@ class repair_cancel(osv.osv_memory):
         @param context: A standard dictionary 
         @return: New arch of view.
         """
-        if not context:
+        if context is None:
             context = {}
         res = super(repair_cancel, self).fields_view_get(cr, uid, view_id=view_id, view_type=view_type, context=context, toolbar=toolbar,submenu=False)
         record_id = context and context.get('active_id', False) or False        
diff --git a/addons/mrp_repair/wizard/make_invoice.py b/addons/mrp_repair/wizard/make_invoice.py
index f3c9f6b36ed..2cb6409348e 100644
--- a/addons/mrp_repair/wizard/make_invoice.py
+++ b/addons/mrp_repair/wizard/make_invoice.py
@@ -39,7 +39,7 @@ class make_invoice(osv.osv_memory):
         @param context: A standard dictionary
         @return: Loads the view of new invoice(s).
         """
-        if not context:
+        if context is None:
             context = {}
         inv = self.browse(cr, uid, ids[0], context=context)
         order_obj = self.pool.get('mrp.repair')
diff --git a/addons/mrp_subproduct/mrp_subproduct.py b/addons/mrp_subproduct/mrp_subproduct.py
index c858aae0281..3229cdce33c 100644
--- a/addons/mrp_subproduct/mrp_subproduct.py
+++ b/addons/mrp_subproduct/mrp_subproduct.py
@@ -41,8 +41,6 @@ class mrp_subproduct(osv.osv):
         @param product_id: Changed product_id
         @return: Dictionary of changed values
         """
-        if not context:
-            context = {}
         if product_id:
             prod = self.pool.get('product.product').browse(cr, uid, product_id, context=context)
             v = {'product_uom': prod.uom_id.id}
diff --git a/addons/outlook/installer.py b/addons/outlook/installer.py
index 6b571b7b70a..143567dd7cf 100755
--- a/addons/outlook/installer.py
+++ b/addons/outlook/installer.py
@@ -30,8 +30,6 @@ class outlook_installer(osv.osv_memory):
     _inherit = 'res.config.installer'
 
     def default_get(self, cr, uid, fields, context=None):
-        if not context:
-            context = {}
         data = super(outlook_installer, self).default_get(cr, uid, fields, context=context)
         data['doc_file'] = 'http://doc.openerp.com/book/2/2_6_Comms/2_6_Comms_outlook.html'
         file = open(addons.get_module_resource('outlook','plugin','openerp-outlook-addin.exe'), 'r')
diff --git a/addons/point_of_sale/account_bank_statement.py b/addons/point_of_sale/account_bank_statement.py
index fa54ab265b2..edcf8573451 100644
--- a/addons/point_of_sale/account_bank_statement.py
+++ b/addons/point_of_sale/account_bank_statement.py
@@ -52,7 +52,7 @@ class account_cash_statement(osv.osv):
             return True
 
     def _user_allow(self, cr, uid, statement_id, context=None):
-        if not context:
+        if context is None:
             context = {}
         statement = self.browse(cr, uid, statement_id, context=context)
         if (not statement.journal_id.journal_users) and uid == 1: return True
diff --git a/addons/point_of_sale/point_of_sale.py b/addons/point_of_sale/point_of_sale.py
index 939f5dbe0e0..f603244d771 100644
--- a/addons/point_of_sale/point_of_sale.py
+++ b/addons/point_of_sale/point_of_sale.py
@@ -60,8 +60,6 @@ class pos_order(osv.osv):
     _order = "date_order, create_date desc"
 
     def unlink(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for rec in self.browse(cr, uid, ids, context=context):
             for rec_statement in rec.statement_ids:
                 if (rec_statement.statement_id and rec_statement.statement_id.state == 'confirm') or rec.state == 'done':
@@ -72,8 +70,6 @@ class pos_order(osv.osv):
         """ Changed price list on_change of partner_id"""
         if not part:
             return {'value': {}}
-        if not context:
-            context = {}
         pricelist = self.pool.get('res.partner').browse(cr, uid, part, context=context).property_product_pricelist.id
         return {'value': {'pricelist_id': pricelist}}
 
@@ -81,8 +77,6 @@ class pos_order(osv.osv):
         """ Calculates amount_tax of order line
         @param field_names: Names of fields.
         @return: Dictionary of values """
-        if not context:
-            context = {}
         cr.execute("""
             SELECT
                 p.id,
@@ -109,8 +103,6 @@ class pos_order(osv.osv):
         @return: Dictionary of values """
         res = {}
         val = None
-        if not context:
-            context = {}
         for order in self.browse(cr, uid, ids, context=context):
             cr.execute("SELECT date_payment FROM pos_order WHERE id = %s", (order.id,))
             date_p = cr.fetchone()
@@ -161,8 +153,6 @@ class pos_order(osv.osv):
         tax_obj = self.pool.get('account.tax')
         cur_obj = self.pool.get('res.currency')
         res = {}
-        if not context:
-            context = {}
         for order in self.browse(cr, uid, ids, context=context):
             res[order.id] = {
                 'amount_paid': 0.0,
@@ -203,8 +193,6 @@ class pos_order(osv.osv):
     def copy(self, cr, uid, id, default=None, context=None):
         if not default:
             default = {}
-        if not context:
-            context = {}
         default.update({
             'state': 'draft',
             'partner_id': False,
@@ -299,8 +287,6 @@ class pos_order(osv.osv):
         @param name: Names of fields.
         @return: pricelist ID
         """
-        if not context:
-            context = {}
         pricelist = self.pool.get('product.pricelist').search(cr, uid, [('name', '=', 'Public Pricelist')], context=context)
         return pricelist and pricelist[0] or False
 
@@ -349,8 +335,6 @@ class pos_order(osv.osv):
         """ Test all amount is paid for this order
         @return: True
         """
-        if not context:
-            context = {}
         for order in self.browse(cr, uid, ids, context=context):
             if order.lines and not order.amount_total:
                 return True
@@ -425,8 +409,6 @@ class pos_order(osv.osv):
         property_obj = self.pool.get("ir.property")
         move_obj=self.pool.get('stock.move')
         pick_name = self.pool.get('ir.sequence').get(cr, uid, 'stock.picking.out')
-        if not context:
-            context = {}
         orders = self.browse(cr, uid, ids, context=context)
         for order in orders:
             if not order.picking_id:
@@ -516,8 +498,6 @@ class pos_order(osv.osv):
         """ Changes order state to cancel
         @return: True
         """
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state': 'cancel'}, context=context)
         self.cancel_picking(cr, uid, ids, context=context)
         return True
@@ -528,8 +508,6 @@ class pos_order(osv.osv):
         statement_line_obj = self.pool.get('account.bank.statement.line')
         prod_obj = self.pool.get('product.product')
         property_obj = self.pool.get('ir.property')
-        if not context:
-            context = {}
         curr_c = self.pool.get('res.users').browse(cr, uid, uid, context=context).company_id
         curr_company = curr_c.id
         order = self.browse(cr, uid, order_id, context=context)
@@ -576,8 +554,6 @@ class pos_order(osv.osv):
 
     def add_product(self, cr, uid, order_id, product_id, qty, context=None):
         """Create a new order line the order"""
-        if not context:
-            context = {}
         line_obj = self.pool.get('pos.order.line')
         values = self.read(cr, uid, order_id, ['partner_id', 'pricelist_id'])
 
@@ -600,8 +576,6 @@ class pos_order(osv.osv):
     def refund(self, cr, uid, ids, context=None):
         """Create a copy of order  for refund order"""
         clone_list = []
-        if not context:
-            context = {}
         line_obj = self.pool.get('pos.order.line')
 
         for order in self.browse(cr, uid, ids, context=context):
@@ -630,8 +604,6 @@ class pos_order(osv.osv):
         inv_line_ref = self.pool.get('account.invoice.line')
         product_obj = self.pool.get('product.product')
         inv_ids = []
-        if not context:
-            context = {}
 
         for order in self.pool.get('pos.order').browse(cr, uid, ids, context=context):
             if order.invoice_id:
@@ -692,8 +664,6 @@ class pos_order(osv.osv):
         account_tax_obj = self.pool.get('account.tax')
         res_obj=self.pool.get('res.users')
         property_obj=self.pool.get('ir.property')
-        if not context:
-            context = {}
         period = account_period_obj.find(cr, uid, context=context)[0]
 
         for order in self.browse(cr, uid, ids, context=context):
@@ -885,8 +855,6 @@ class pos_order(osv.osv):
 
     def cancel_picking(self, cr, uid, ids, context=None):
         stock_picking_obj = self.pool.get('stock.picking')
-        if not context:
-            context = {}
         for order in self.browse(cr, uid, ids, context=context):
             for picking in order.pickings:
                 stock_picking_obj.unlink(cr, uid, [picking.id], context=context)
@@ -896,8 +864,6 @@ class pos_order(osv.osv):
     def action_payment(self, cr, uid, ids, context=None):
         vals = {'state': 'payment'}
         sequence_obj = self.pool.get('ir.sequence')
-        if not context:
-            context = {}
         for pos in self.browse(cr, uid, ids, context=context):
             create_contract_nb = False
             for line in pos.lines:
@@ -910,7 +876,7 @@ class pos_order(osv.osv):
         self.write(cr, uid, ids, vals, context=context)
 
     def action_paid(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         if context.get('flag', False):
             self.create_picking(cr, uid, ids, context=None)
@@ -920,14 +886,10 @@ class pos_order(osv.osv):
         return True
 
     def action_cancel(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state': 'cancel'}, context=context)
         return True
 
     def action_done(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for order in self.browse(cr, uid, ids, context=context):
             if not order.journal_entry:
                 self.create_account_move(cr, uid, ids, context=None)
@@ -975,8 +937,6 @@ class pos_order_line(osv.osv):
 
     def _get_amount(self, cr, uid, ids, field_name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         for line in self.browse(cr, uid, ids, context=context):
             price = self.price_by_product(cr, uid, ids, line.order_id.pricelist_id.id, line.product_id.id, line.qty, line.order_id.partner_id.id)
             res[line.id] = price
@@ -984,8 +944,6 @@ class pos_order_line(osv.osv):
 
     def _amount_line_ttc(self, cr, uid, ids, field_name, arg, context=None):
         res = dict.fromkeys(ids, 0.0)
-        if not context:
-            context = {}
         account_tax_obj = self.pool.get('account.tax')
         self.price_by_product_multi(cr, uid, ids)
         for line in self.browse(cr, uid, ids, context=context):
@@ -1005,8 +963,6 @@ class pos_order_line(osv.osv):
 
     def _amount_line(self, cr, uid, ids, field_name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         self.price_by_product_multi(cr, uid, ids)
         for line in self.browse(cr, uid, ids, context=context):
             if line.discount!=0.0:
@@ -1017,8 +973,6 @@ class pos_order_line(osv.osv):
 
     def _amount_line_all(self, cr, uid, ids, field_names, arg, context=None):
         res = dict([(i, {}) for i in ids])
-        if not context:
-            context = {}
         account_tax_obj = self.pool.get('account.tax')
 
         self.price_by_product_multi(cr, uid, ids)
@@ -1155,8 +1109,6 @@ class pos_order_line(osv.osv):
             return {'value': {'notice': 'No Discount', 'price_ded': price * discount * 0.01 or 0.0}}
 
     def onchange_qty(self, cr, uid, ids, discount, qty, price, context=None):
-        if not context:
-            context = {}
         subtotal = qty * price
         if discount:
             subtotal = subtotal - (subtotal * discount / 100)
@@ -1189,15 +1141,11 @@ class pos_order_line(osv.osv):
         }
 
     def create(self, cr, user, vals, context=None):
-        if not context:
-            context = {}
         if vals.get('product_id'):
             return super(pos_order_line, self).create(cr, user, vals, context=context)
         return False
 
     def write(self, cr, user, ids, values, context=None):
-        if not context:
-            context = {}
         if 'product_id' in values and not values['product_id']:
             return False
         return super(pos_order_line, self).write(cr, user, ids, values, context=context)
diff --git a/addons/point_of_sale/wizard/all_closed_cashbox_of_the_day.py b/addons/point_of_sale/wizard/all_closed_cashbox_of_the_day.py
index 139eea8301a..330668548e4 100644
--- a/addons/point_of_sale/wizard/all_closed_cashbox_of_the_day.py
+++ b/addons/point_of_sale/wizard/all_closed_cashbox_of_the_day.py
@@ -34,7 +34,7 @@ class all_closed_cashbox_of_the_day(osv.osv_memory):
              @param context: A standard dictionary
              @return : retrun report
         """
-        if not context:
+        if context is None:
             context = {}
         datas = {'ids': context.get('active_ids', [])}
         return {
diff --git a/addons/point_of_sale/wizard/pos_box_entries.py b/addons/point_of_sale/wizard/pos_box_entries.py
index d6441c467f9..dcc9779a903 100644
--- a/addons/point_of_sale/wizard/pos_box_entries.py
+++ b/addons/point_of_sale/wizard/pos_box_entries.py
@@ -61,8 +61,6 @@ class pos_box_entries(osv.osv_memory):
              @param context: A standard dictionary
              @return :Return of operation of product
         """
-        if not context:
-            context = {}
         product_obj = self.pool.get('product.product')
         ids = product_obj.search(cr, uid, [('income_pdt', '=', True)], context=context)
         res = product_obj.read(cr, uid, ids, ['id', 'name'], context=context)
@@ -97,8 +95,6 @@ class pos_box_entries(osv.osv_memory):
         res_obj = self.pool.get('res.users')
         product_obj = self.pool.get('product.product')
         bank_statement = self.pool.get('account.bank.statement.line')
-        if not context:
-            context = {}
         for data in  self.read(cr, uid, ids, context=context):
             vals = {}
             curr_company = res_obj.browse(cr, uid, uid, context=context).company_id.id
diff --git a/addons/point_of_sale/wizard/pos_box_out.py b/addons/point_of_sale/wizard/pos_box_out.py
index 80e0ae7fe61..a05c5f579e1 100644
--- a/addons/point_of_sale/wizard/pos_box_out.py
+++ b/addons/point_of_sale/wizard/pos_box_out.py
@@ -41,8 +41,6 @@ class pos_box_out(osv.osv_memory):
              @return :Return of operation of product
         """
         product_obj = self.pool.get('product.product')
-        if not context:
-            context = {}
         company_id = self.pool.get('res.users').browse(cr, uid, uid, context=context).company_id.id
         ids = product_obj.search(cr, uid, ['&', ('expense_pdt', '=', True), '|', ('company_id', '=', company_id), ('company_id', '=', None)], context=context)
         res = product_obj.read(cr, uid, ids, ['id', 'name'], context=context)
@@ -77,8 +75,6 @@ class pos_box_out(osv.osv_memory):
         product_obj = self.pool.get('product.template')
         productp_obj = self.pool.get('product.product')
         res_obj = self.pool.get('res.users')
-        if not context:
-            context = {}
         for data in  self.read(cr, uid, ids, context=context):
             curr_company = res_obj.browse(cr, uid, uid, context=context).company_id.id
             statement_id = statement_obj.search(cr, uid, [('journal_id', '=', data['journal_id']), ('company_id', '=', curr_company), ('user_id', '=', uid), ('state', '=', 'open')], context=context)
diff --git a/addons/point_of_sale/wizard/pos_close_statement.py b/addons/point_of_sale/wizard/pos_close_statement.py
index 03f26b7f0d8..222338f6e10 100644
--- a/addons/point_of_sale/wizard/pos_close_statement.py
+++ b/addons/point_of_sale/wizard/pos_close_statement.py
@@ -43,8 +43,6 @@ class pos_close_statement(osv.osv_memory):
         j_ids = map(lambda x1: x1[0], cr.fetchall())
         journal_ids = journal_obj.search(cr, uid, [('auto_cash', '=', True), ('type', '=', 'cash'), ('id', 'in', j_ids)], context=context)
         ids = statement_obj.search(cr, uid, [('state', '!=', 'confirm'), ('user_id', '=', uid), ('journal_id', 'in', journal_ids)], context=context)
-        if not context:
-            context = {}
         for journal in journal_obj.browse(cr, uid, journal_ids, context=context):
             if not ids:
                 raise osv.except_osv(_('Message'), _('Cash registers are already closed.'))
diff --git a/addons/point_of_sale/wizard/pos_discount.py b/addons/point_of_sale/wizard/pos_discount.py
index 149f6260ad3..97e94620820 100644
--- a/addons/point_of_sale/wizard/pos_discount.py
+++ b/addons/point_of_sale/wizard/pos_discount.py
@@ -43,7 +43,7 @@ class pos_discount(osv.osv_memory):
          @param context: A standard dictionary
          @return: New arch of view with new columns.
         """
-        if not context:
+        if context is None:
             context = {}
         super(pos_discount, self).view_init(cr, uid, fields_list, context=context)
         record_id = context and context.get('active_id', False) or False
diff --git a/addons/point_of_sale/wizard/pos_open_statement.py b/addons/point_of_sale/wizard/pos_open_statement.py
index 0b10f0cab42..71be59c0b6d 100644
--- a/addons/point_of_sale/wizard/pos_open_statement.py
+++ b/addons/point_of_sale/wizard/pos_open_statement.py
@@ -40,7 +40,7 @@ class pos_open_statement(osv.osv_memory):
         statement_obj = self.pool.get('account.bank.statement')
         sequence_obj = self.pool.get('ir.sequence')
         journal_obj = self.pool.get('account.journal')
-        if not context:
+        if context is None:
             context = {}
         company_id = self.pool.get('res.users').browse(cr, uid, uid, context=context).company_id.id
         cr.execute("SELECT DISTINCT journal_id FROM pos_journal_users "
diff --git a/addons/point_of_sale/wizard/pos_payment.py b/addons/point_of_sale/wizard/pos_payment.py
index b8043d658ef..fe3dd14db73 100644
--- a/addons/point_of_sale/wizard/pos_payment.py
+++ b/addons/point_of_sale/wizard/pos_payment.py
@@ -81,7 +81,7 @@ class pos_make_payment(osv.osv_memory):
         return res
 
     def view_init(self, cr, uid, fields_list, context=None):
-        if not context:
+        if context is None:
             context = {}
         super(pos_make_payment, self).view_init(cr, uid, fields_list, context=context)
         active_id = context and context.get('active_id', False) or False
@@ -142,7 +142,7 @@ class pos_make_payment(osv.osv_memory):
         if the order is paid print invoice (if wanted) or ticket.
         """
         order_obj = self.pool.get('pos.order')
-        if not context:
+        if context is None:
             context = {}
         active_id = context and context.get('active_id', False)
         order = order_obj.browse(cr, uid, active_id, context=context)
@@ -188,7 +188,7 @@ class pos_make_payment(osv.osv_memory):
         """
           Create  a invoice
         """
-        if not context:
+        if context is None:
             context = {}
         active_ids = [context and context.get('active_id', False)]
         datas = {'ids': active_ids}
@@ -207,7 +207,7 @@ class pos_make_payment(osv.osv_memory):
          @param context: A standard dictionary
          @return : retrun report
         """
-        if not context:
+        if context is None:
             context = {}
         active_id = context.get('active_id', [])
         datas = {'ids' : [active_id]}
diff --git a/addons/point_of_sale/wizard/pos_receipt.py b/addons/point_of_sale/wizard/pos_receipt.py
index 19ce8c2c359..71efee85b7c 100644
--- a/addons/point_of_sale/wizard/pos_receipt.py
+++ b/addons/point_of_sale/wizard/pos_receipt.py
@@ -35,8 +35,6 @@ class pos_receipt(osv.osv_memory):
         @param context: A standard dictionary
         @return: New arch of view with new columns.
         """
-        if not context:
-            context = {}
         order_lst = self. pool.get('pos.order').browse(cr, uid, context['active_id'], context=context)
 
     def print_report(self, cr, uid, ids, context=None):
@@ -48,7 +46,7 @@ class pos_receipt(osv.osv_memory):
         @param context: A standard dictionary
         @return : retrun report
         """
-        if not context:
+        if context is None:
             context = {}
         datas = {'ids': context.get('active_ids', [])}
         return {
diff --git a/addons/point_of_sale/wizard/pos_return.py b/addons/point_of_sale/wizard/pos_return.py
index 9d85d3c84fe..810ef86ec7b 100644
--- a/addons/point_of_sale/wizard/pos_return.py
+++ b/addons/point_of_sale/wizard/pos_return.py
@@ -44,9 +44,9 @@ class pos_return(osv.osv_memory):
 
         res = super(pos_return, self).default_get(cr, uid, fields, context=context)
         order_obj = self.pool.get('pos.order')
-        active_ids = context.get('active_ids')
-        if not context:
+        if context is None:
             context={}
+        active_ids = context.get('active_ids')
         for order in order_obj.browse(cr, uid, active_ids, context=context):
             for line in order.lines:
                 if 'return%s'%(line.id) in fields:
@@ -64,7 +64,7 @@ class pos_return(osv.osv_memory):
         """
         res = super(pos_return, self).view_init(cr, uid, fields_list, context=context)
         order_obj=self.pool.get('pos.order')
-        if not context:
+        if context is None:
             context={}
 
         active_ids=context.get('active_ids')
@@ -89,7 +89,7 @@ class pos_return(osv.osv_memory):
 
         """
         result = super(pos_return, self).fields_view_get(cr, uid, view_id, view_type, context, toolbar,submenu)
-        if not context:
+        if context is None:
             context={}
         active_model = context.get('active_model')
         if not active_model and active_model != 'pos.order':
@@ -143,7 +143,7 @@ class pos_return(osv.osv_memory):
              @return: Return the add product form again for adding more product
 
         """
-        if not context:
+        if context is None:
             context = {}
         current_rec = self.read(cr, uid, data[0], context=context)
         order_obj =self.pool.get('pos.order')
@@ -174,7 +174,7 @@ class pos_return(osv.osv_memory):
             'type': 'ir.actions.act_window',
         }
     def create_returns2(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         active_id = context.get('active_id', False)
         order_obj =self.pool.get('pos.order')
@@ -270,7 +270,7 @@ class add_product(osv.osv_memory):
              @param context: A standard dictionary
              @return : Retrun the add product form again for adding more product
         """
-        if not context:
+        if context is None:
             context = {}
 
         active_id=context.get('active_id', False)
@@ -336,6 +336,7 @@ class add_product(osv.osv_memory):
         }
 
     def close_action(self, cr, uid, ids, context=None):
+        if context is None: context = {}
         active_ids=context.get('active_ids', False)
         order_obj = self.pool.get('pos.order')
         lines_obj = self.pool.get('pos.order.line')
diff --git a/addons/point_of_sale/wizard/pos_sales_user.py b/addons/point_of_sale/wizard/pos_sales_user.py
index 29837b1cc3a..e17aff8bdca 100644
--- a/addons/point_of_sale/wizard/pos_sales_user.py
+++ b/addons/point_of_sale/wizard/pos_sales_user.py
@@ -42,7 +42,7 @@ class pos_sale_user(osv.osv_memory):
          @param context: A standard dictionary
          @return : return report
         """
-        if not context:
+        if context is None:
             context = {}
 
         datas = {'ids': context.get('active_ids', [])}
diff --git a/addons/point_of_sale/wizard/pos_sales_user_current_user.py b/addons/point_of_sale/wizard/pos_sales_user_current_user.py
index 86973d5efe4..100154ac734 100644
--- a/addons/point_of_sale/wizard/pos_sales_user_current_user.py
+++ b/addons/point_of_sale/wizard/pos_sales_user_current_user.py
@@ -39,7 +39,7 @@ class pos_sales_user_today_current_user(osv.osv_memory):
          @param context: A standard dictionary
          @return : retrun report
         """
-        if not context:
+        if context is None:
             context = {}
 
         datas = {'ids': context.get('active_ids', [])}
diff --git a/addons/point_of_sale/wizard/pos_sales_user_today.py b/addons/point_of_sale/wizard/pos_sales_user_today.py
index 5645a879e4d..33c9dc8f3fc 100644
--- a/addons/point_of_sale/wizard/pos_sales_user_today.py
+++ b/addons/point_of_sale/wizard/pos_sales_user_today.py
@@ -40,7 +40,7 @@ class pos_sales_user_today(osv.osv_memory):
          @param context: A standard dictionary
          @return : retrun report
         """
-        if not context:
+        if context is None:
             context = {}
 
         datas = {'ids': context.get('active_ids', [])}
diff --git a/addons/point_of_sale/wizard/pos_scan_product.py b/addons/point_of_sale/wizard/pos_scan_product.py
index cbf5315c471..49cd32eba4d 100644
--- a/addons/point_of_sale/wizard/pos_scan_product.py
+++ b/addons/point_of_sale/wizard/pos_scan_product.py
@@ -37,7 +37,7 @@ class pos_scan_product(osv.osv_memory):
          @param context: A standard dictionary 
          @return : retrun gencod
         """
-        if not context:
+        if context is None:
             context = {}
         data=self.read(cr, uid, ids)[0]
         record_id = context and context.get('active_id',False)
diff --git a/addons/process/process.py b/addons/process/process.py
index 676b75ae47e..e8c524b6857 100644
--- a/addons/process/process.py
+++ b/addons/process/process.py
@@ -53,8 +53,6 @@ class process_process(osv.osv):
     }
 
     def search_by_model(self, cr, uid, res_model, context=None):
-        if not context:
-            context = {}
         pool = pooler.get_pool(cr.dbname)
         model_ids = (res_model or None) and pool.get('ir.model').search(cr, uid, [('model', '=', res_model)])
 
@@ -80,8 +78,6 @@ class process_process(osv.osv):
         return result
 
     def graph_get(self, cr, uid, id, res_model, res_id, scale, context=None):
-        if not context:
-            context = {}
 
         pool = pooler.get_pool(cr.dbname)
 
@@ -256,9 +252,6 @@ class process_process(osv.osv):
         if not default:
             default = {}
         
-        if not context:
-            context = {}
-
         pool = pooler.get_pool(cr.dbname)
         process = pool.get('process.process').browse(cr, uid, [id], context=context)[0]
 
@@ -319,8 +312,6 @@ class process_node(osv.osv):
     def copy_data(self, cr, uid, id, default=None, context=None):
         if not default:
             default = {}
-        if not context:
-            context = {}
         default.update({
             'transition_in': [],
             'transition_out': []
@@ -379,9 +370,6 @@ class process_transition_action(osv.osv):
         if not default:
             default = {}
             
-        if not context:
-            context = {}
-
         state = self.pool.get('process.transition.action').browse(cr, uid, [id], context=context)[0].state
         if state:
             default['state'] = state
diff --git a/addons/procurement/procurement.py b/addons/procurement/procurement.py
index 939dd46496c..2c451dcf9bf 100644
--- a/addons/procurement/procurement.py
+++ b/addons/procurement/procurement.py
@@ -69,8 +69,6 @@ class StockMove(osv.osv):
     
     def copy(self, cr, uid, id, default=None, context=None):
         default = default or {}
-        if not context:
-            context = {}
         default['procurements'] = []
         return super(StockMove, self).copy(cr, uid, id, default, context=context)
 
@@ -132,8 +130,6 @@ class procurement_order(osv.osv):
     def unlink(self, cr, uid, ids, context=None):
         procurements = self.read(cr, uid, ids, ['state'])
         unlink_ids = []
-        if not context:
-            context = {}
         for s in procurements:
             if s['state'] in ['draft','cancel']:
                 unlink_ids.append(s['id'])
@@ -148,8 +144,6 @@ class procurement_order(osv.osv):
         @param product_id: Changed id of product.
         @return: Dictionary of values.
         """
-        if not context:
-            context = {}
         if product_id:
             w = self.pool.get('product.product').browse(cr, uid, product_id, context=context)
             v = {
@@ -169,16 +163,12 @@ class procurement_order(osv.osv):
         """ Checks if move is cancelled or not.
         @return: True or False.
         """
-        if not context:
-            context = {}
         return all(procurement.move_id.state == 'cancel' for procurement in self.browse(cr, uid, ids, context=context))
 
     def check_move_done(self, cr, uid, ids, context=None):
         """ Checks if move is done or not.
         @return: True or False.
         """
-        if not context:
-            context = {}
         return all(procurement.move_id.state == 'done' for procurement in self.browse(cr, uid, ids, context=context))
 
     #
@@ -213,8 +203,6 @@ class procurement_order(osv.osv):
         """ Finds quantity of product used in procurement.
         @return: Quantity of product.
         """
-        if not context:
-            context = {}
         proc = self.browse(cr, uid, id, context=context)
         result = self._quantity_compute_get(cr, uid, proc, context=context)
         if not result:
@@ -225,15 +213,13 @@ class procurement_order(osv.osv):
         """ Finds UoM of product used in procurement.
         @return: UoM of product.
         """
-        if not context:
-            context = {}
         proc = self.browse(cr, uid, id, context=context)
         result = self._uom_compute_get(cr, uid, proc, context=context)
         if not result:
             result = proc.product_uom.id
         return result
 
-    def check_waiting(self, cr, uid, ids, context=[]):
+    def check_waiting(self, cr, uid, ids, context=None):
         """ Checks state of move.
         @return: True or False
         """
@@ -243,8 +229,6 @@ class procurement_order(osv.osv):
         return False
 
     def check_produce_service(self, cr, uid, procurement, context=None):
-        if not context:
-            context = {}
         return False
 
     def check_produce_product(self, cr, uid, procurement, context=None):
@@ -252,8 +236,6 @@ class procurement_order(osv.osv):
         @param procurement: Current procurement.
         @return: True or False.
         """
-        if not context:
-            context = {}
         return True
 
     def check_make_to_stock(self, cr, uid, ids, context=None):
@@ -261,8 +243,6 @@ class procurement_order(osv.osv):
         @return: True or False
         """
         ok = True
-        if not context:
-            context = {}
         for procurement in self.browse(cr, uid, ids, context=context):
             if procurement.product_id.type == 'service':
                 ok = ok and self._check_make_to_stock_service(cr, uid, procurement, context)
@@ -275,8 +255,6 @@ class procurement_order(osv.osv):
         @return: True or Product Id.
         """
         res = True
-        if not context:
-            context = {}
         user = self.pool.get('res.users').browse(cr, uid, uid, context=context)
         for procurement in self.browse(cr, uid, ids, context=context):
             if procurement.product_id.product_tmpl_id.supply_method <> 'produce':
@@ -334,8 +312,6 @@ class procurement_order(osv.osv):
         @return: True
         """
         move_obj = self.pool.get('stock.move')
-        if not context:
-            context = {}
         for procurement in self.browse(cr, uid, ids, context=context):
             if procurement.product_qty <= 0.00:
                 raise osv.except_osv(_('Data Insufficient !'), 
@@ -383,8 +359,6 @@ class procurement_order(osv.osv):
         @return: True or move id.
         """
         ok = True
-        if not context:
-            context = {}
         if procurement.move_id:
             id = procurement.move_id.id
             if not (procurement.move_id.state in ('done','assigned','cancel')):
@@ -484,8 +458,6 @@ class procurement_order(osv.osv):
         ''' Runs through scheduler.
         @param use_new_cursor: False or the dbname
         '''
-        if not context:
-            context={}
         self._procure_confirm(cr, uid, use_new_cursor=use_new_cursor, context=context)
         self._procure_orderpoint_confirm(cr, uid, automatic=automatic,\
                 use_new_cursor=use_new_cursor, context=context)
@@ -552,8 +524,6 @@ class stock_warehouse_orderpoint(osv.osv):
         @param warehouse_id: Changed id of warehouse.
         @return: Dictionary of values.
         """
-        if not context:
-            context = {}
         if warehouse_id:
             w = self.pool.get('stock.warehouse').browse(cr, uid, warehouse_id, context=context)
             v = {'location_id': w.lot_stock_id.id}
@@ -565,8 +535,6 @@ class stock_warehouse_orderpoint(osv.osv):
         @param product_id: Changed id of product.
         @return: Dictionary of values.
         """
-        if not context:
-            context = {}
         if product_id:
             prod = self.pool.get('product.product').browse(cr, uid, product_id, context=context)
             v = {'product_uom': prod.uom_id.id}
@@ -576,8 +544,6 @@ class stock_warehouse_orderpoint(osv.osv):
     def copy(self, cr, uid, id, default=None, context=None):
         if not default:
             default = {}
-        if not context:
-            context = {}
         default.update({
             'name': self.pool.get('ir.sequence').get(cr, uid, 'stock.orderpoint') or '',
         })
diff --git a/addons/procurement/schedulers.py b/addons/procurement/schedulers.py
index b5afe9c35d7..9c83499f0a5 100644
--- a/addons/procurement/schedulers.py
+++ b/addons/procurement/schedulers.py
@@ -43,7 +43,7 @@ class procurement_order(osv.osv):
         @param context: A standard dictionary for contextual values
         @return:  Dictionary of values        
         '''
-        if not context:
+        if context is None:
             context = {}
 
         try:
@@ -148,7 +148,7 @@ class procurement_order(osv.osv):
         @param context: A standard dictionary for contextual values
         @return:  Dictionary of values
         """
-        if not context:
+        if context is None:
             context = {}
         product_obj = self.pool.get('product.product')
         proc_obj = self.pool.get('procurement.order')
@@ -200,7 +200,7 @@ class procurement_order(osv.osv):
         @return:  Dictionary of values
         """        
         '''
-        if not context:
+        if context is None:
             context = {}
         if use_new_cursor:
             cr = pooler.get_db(use_new_cursor).cursor()
diff --git a/addons/procurement/wizard/make_procurement_product.py b/addons/procurement/wizard/make_procurement_product.py
index 1b45517339a..0f5acf2f5c8 100644
--- a/addons/procurement/wizard/make_procurement_product.py
+++ b/addons/procurement/wizard/make_procurement_product.py
@@ -62,8 +62,6 @@ class make_procurement(osv.osv_memory):
         @param context: A standard dictionary
         @return: A dictionary which loads Procurement form view.
         """
-        if not context:
-            context = {}
         user = self.pool.get('res.users').browse(cr, uid, uid, context=context).login
         wh_obj = self.pool.get('stock.warehouse')
         procurement_obj = self.pool.get('procurement.order')
@@ -111,7 +109,7 @@ class make_procurement(osv.osv_memory):
         @param context: A standard dictionary
         @return: A dictionary which of fields with values.
         """
-        if not context:
+        if context is None:
             context = {}
         record_id = context and context.get('active_id', False) or False
 
diff --git a/addons/procurement/wizard/mrp_procurement.py b/addons/procurement/wizard/mrp_procurement.py
index 7765728a834..7fa28adf5fe 100644
--- a/addons/procurement/wizard/mrp_procurement.py
+++ b/addons/procurement/wizard/mrp_procurement.py
@@ -28,8 +28,6 @@ class procurement_compute(osv.osv_memory):
 
     def _procure_calculation_procure(self, cr, uid, ids, context=None):
         try:
-            if not context:
-                context = {}
             proc_obj = self.pool.get('procurement.order')
             proc_obj._procure_confirm(cr, uid, use_new_cursor=cr.dbname, context=context)
         finally:
@@ -44,8 +42,6 @@ class procurement_compute(osv.osv_memory):
          @param ids: List of IDs selected
          @param context: A standard dictionary
         """
-        if not context:
-            context = {}
         threaded_calculation = threading.Thread(target=self._procure_calculation_procure, args=(cr, uid, ids, context))
         threaded_calculation.start()
         return {}
diff --git a/addons/procurement/wizard/orderpoint_procurement.py b/addons/procurement/wizard/orderpoint_procurement.py
index 8c251846f7b..d94e6753231 100644
--- a/addons/procurement/wizard/orderpoint_procurement.py
+++ b/addons/procurement/wizard/orderpoint_procurement.py
@@ -47,8 +47,6 @@ class procurement_compute(osv.osv_memory):
         @param ids: List of IDs selected
         @param context: A standard dictionary
         """
-        if not context:
-            context = {}
         proc_obj = self.pool.get('procurement.order')
         for proc in self.browse(cr, uid, ids, context=context):
             proc_obj._procure_orderpoint_confirm(cr, uid, automatic=proc.automatic, use_new_cursor=cr.dbname, context=context)
@@ -63,8 +61,6 @@ class procurement_compute(osv.osv_memory):
         @param ids: List of IDs selected
         @param context: A standard dictionary
         """
-        if not context:
-            context = {}
         threaded_calculation = threading.Thread(target=self._procure_calculation_orderpoint, args=(cr, uid, ids, context))
         threaded_calculation.start()
         return {}
diff --git a/addons/procurement/wizard/schedulers_all.py b/addons/procurement/wizard/schedulers_all.py
index 9e9ca3d2487..5fae2760edf 100644
--- a/addons/procurement/wizard/schedulers_all.py
+++ b/addons/procurement/wizard/schedulers_all.py
@@ -44,8 +44,6 @@ class procurement_compute_all(osv.osv_memory):
         @param context: A standard dictionary
         """
         proc_obj = self.pool.get('procurement.order')
-        if not context:
-            context = {}
         for proc in self.browse(cr, uid, ids, context=context):
             proc_obj.run_scheduler(cr, uid, automatic=proc.automatic, use_new_cursor=cr.dbname,\
                     context=context)
@@ -59,8 +57,6 @@ class procurement_compute_all(osv.osv_memory):
         @param ids: List of IDs selected
         @param context: A standard dictionary
         """
-        if not context:
-            context = {}
         threaded_calculation = threading.Thread(target=self._procure_calculation_all, args=(cr, uid, ids, context))
         threaded_calculation.start()
         return {}
diff --git a/addons/product/pricelist.py b/addons/product/pricelist.py
index fea11385946..f9b8ddf86cc 100644
--- a/addons/product/pricelist.py
+++ b/addons/product/pricelist.py
@@ -40,8 +40,6 @@ class price_type(osv.osv):
         mf = self.pool.get('ir.model.fields')
         ids = mf.search(cr, uid, [('model','in', (('product.product'),('product.template'))), ('ttype','=','float')], context=context)
         res = []
-        if not context:
-            context = {}
         for field in mf.browse(cr, uid, ids, context=context):
             res.append((field.name, field.field_description))
         return res
@@ -84,8 +82,6 @@ product_pricelist_type()
 
 class product_pricelist(osv.osv):
     def _pricelist_type_get(self, cr, uid, context=None):
-        if not context:
-            context = {}
         pricelist_type_obj = self.pool.get('product.pricelist.type')
         pricelist_type_ids = pricelist_type_obj.search(cr, uid, [], order='name')
         pricelist_types = pricelist_type_obj.read(cr, uid, pricelist_type_ids, ['key','name'], context=context)
@@ -112,8 +108,6 @@ class product_pricelist(osv.osv):
         result= []
         if not all(ids):
             return result
-        if not context:
-            context = {}
         for pl in self.browse(cr, uid, ids, context=context):
             name = pl.name + ' ('+ pl.currency_id.name + ')'
             result.append((pl.id,name))
@@ -298,8 +292,6 @@ class product_pricelist(osv.osv):
         return results
 
     def price_get(self, cr, uid, ids, prod_id, qty, partner=None, context=None):
-        if not context:
-            context = {}
         res_multi = self.price_get_multi(cr, uid, pricelist_ids=ids, products_by_qty_by_partner=[(prod_id, qty, partner)], context=context)
         res = res_multi[prod_id]
         res.update({'item_id': {ids[-1]: ids[-1]}})
@@ -478,8 +470,6 @@ class product_pricelist_version(osv.osv):
         return super(product_pricelist_version, self).copy(cr, uid, id, default, context)
 
     def _check_date(self, cursor, user, ids, context=None):
-        if not context:
-            context = {}
         for pricelist_version in self.browse(cursor, user, ids, context=context):
             if not pricelist_version.active:
                 continue
@@ -510,8 +500,6 @@ product_pricelist_version()
 
 class product_pricelist_item(osv.osv):
     def _price_field_get(self, cr, uid, context=None):
-        if not context:
-            context = {}
         pt = self.pool.get('product.price.type')
         ids = pt.search(cr, uid, [], context=context)
         result = []
@@ -533,8 +521,6 @@ class product_pricelist_item(osv.osv):
     }
 
     def _check_recursion(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for obj_list in self.browse(cr, uid, ids, context=context):
             if obj_list.base == -1:
                 main_pricelist = obj_list.price_version_id.pricelist_id.id
@@ -579,8 +565,6 @@ class product_pricelist_item(osv.osv):
     def product_id_change(self, cr, uid, ids, product_id, context=None):
         if not product_id:
             return {}
-        if not context:
-            context = {}
         prod = self.pool.get('product.product').read(cr, uid, [product_id], ['code','name'])
         if prod[0]['code']:
             return {'value': {'name': prod[0]['code']}}
diff --git a/addons/product/product.py b/addons/product/product.py
index 067c9643b9a..f4a659bb92d 100644
--- a/addons/product/product.py
+++ b/addons/product/product.py
@@ -51,20 +51,14 @@ class product_uom(osv.osv):
 
     def _factor_inv(self, cursor, user, ids, name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         for uom in self.browse(cursor, user, ids, context=context):
             res[uom.id] = self._compute_factor_inv(uom.factor)
         return res
 
     def _factor_inv_write(self, cursor, user, id, name, value, arg, context=None):
-        if not context:
-            context = {}
         return self.write(cursor, user, id, {'factor': self._compute_factor_inv(value)}, context=context)
 
     def create(self, cr, uid, data, context=None):
-        if not context:
-            context = {}
         if 'factor_inv' in data:
             if data['factor_inv'] <> 1:
                 data['factor'] = self._compute_factor_inv(data['factor_inv'])
@@ -161,8 +155,6 @@ class product_category(osv.osv):
     def name_get(self, cr, uid, ids, context=None):
         if not len(ids):
             return []
-        if not context:
-            context = {}
         reads = self.read(cr, uid, ids, ['name','parent_id'], context=context)
         res = []
         for record in reads:
@@ -173,8 +165,6 @@ class product_category(osv.osv):
         return res
 
     def _name_get_fnc(self, cr, uid, ids, prop, unknow_none, context=None):
-        if not context:
-            context = {}
         res = self.name_get(cr, uid, ids, context=context)
         return dict(res)
 
@@ -197,8 +187,6 @@ class product_category(osv.osv):
     _order = "sequence"
     def _check_recursion(self, cr, uid, ids, context=None):
         level = 100
-        if not context:
-            context = {}
         while len(ids):
             cr.execute('select distinct parent_id from product_category where id IN %s',(tuple(ids),))
             ids = filter(None, map(lambda x:x[0], cr.fetchall()))
@@ -224,8 +212,6 @@ class product_template(osv.osv):
     _description = "Product Template"
     def _calc_seller(self, cr, uid, ids, fields, arg, context=None):
         result = {}
-        if not context:
-            context = {}
         for product in self.browse(cr, uid, ids, context=context):
             for field in fields:
                 result[product.id] = {field:False}
@@ -290,7 +276,7 @@ class product_template(osv.osv):
         return res and res[0] or False
 
     def _default_category(self, cr, uid, context=None):
-        if not context:
+        if context is None:
             context = {}
         if 'categ_id' in context and context['categ_id']:
             return context['categ_id']
@@ -324,16 +310,12 @@ class product_template(osv.osv):
     }
 
     def _check_uom(self, cursor, user, ids, context=None):
-        if not context:
-            context = {}
         for product in self.browse(cursor, user, ids, context=context):
             if product.uom_id.category_id.id <> product.uom_po_id.category_id.id:
                 return False
         return True
 
     def _check_uos(self, cursor, user, ids, context=None):
-        if not context:
-            context = {}
         for product in self.browse(cursor, user, ids, context=context):
             if product.uos_id \
                     and product.uos_id.category_id.id \
@@ -347,7 +329,7 @@ class product_template(osv.osv):
     ]
 
     def name_get(self, cr, user, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         if 'partner_id' in context:
             pass
@@ -357,7 +339,7 @@ product_template()
 
 class product_product(osv.osv):
     def view_header_get(self, cr, uid, view_id, view_type, context=None):
-        if not context:
+        if context is None:
             context = {}
         res = super(product_product, self).view_header_get(cr, uid, view_id, view_type, context)
         if (context.get('categ_id', False)):
@@ -366,7 +348,7 @@ class product_product(osv.osv):
 
     def _product_price(self, cr, uid, ids, name, arg, context=None):
         res = {}
-        if not context:
+        if context is None:
             context = {}
         quantity = context.get('quantity', 1)
         pricelist = context.get('pricelist', False)
@@ -393,8 +375,6 @@ class product_product(osv.osv):
 
     def _product_lst_price(self, cr, uid, ids, name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         product_uom_obj = self.pool.get('product.uom')
         for id in ids:
             res.setdefault(id, 0.0)
@@ -409,8 +389,6 @@ class product_product(osv.osv):
         return res
 
     def _get_partner_code_name(self, cr, uid, ids, product, partner_id, context=None):
-        if not context:
-            context = {}
         for supinfo in product.seller_ids:
             if supinfo.name.id == partner_id:
                 return {'code': supinfo.product_code or product.default_code, 'name': supinfo.product_name or product.name, 'variants': ''}
@@ -419,7 +397,7 @@ class product_product(osv.osv):
 
     def _product_code(self, cr, uid, ids, name, arg, context=None):
         res = {}
-        if not context:
+        if context is None:
             context = {}
         for p in self.browse(cr, uid, ids, context=context):
             res[p.id] = self._get_partner_code_name(cr, uid, [], p, context.get('partner_id', None), context=context)['code']
@@ -427,7 +405,7 @@ class product_product(osv.osv):
 
     def _product_partner_ref(self, cr, uid, ids, name, arg, context=None):
         res = {}
-        if not context:
+        if context is None:
             context = {}
         for p in self.browse(cr, uid, ids, context=context):
             data = self._get_partner_code_name(cr, uid, [], p, context.get('partner_id', None), context=context)
@@ -481,8 +459,6 @@ class product_product(osv.osv):
         return False
 
     def _check_ean_key(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for partner in self.browse(cr, uid, ids, context=context):
             if not partner.ean13:
                 continue
@@ -511,8 +487,6 @@ class product_product(osv.osv):
     def name_get(self, cr, user, ids, context=None):
         if not len(ids):
             return []
-        if not context:
-            context = {}
         def _name_get(d):
             name = d.get('name','')
             code = d.get('default_code',False)
@@ -527,8 +501,6 @@ class product_product(osv.osv):
     def name_search(self, cr, user, name='', args=None, operator='ilike', context=None, limit=100):
         if not args:
             args=[]
-        if not context:
-            context={}
         if name:
             ids = self.search(cr, user, [('default_code',operator,name)]+ args, limit=limit, context=context)
             if not len(ids):
@@ -579,7 +551,7 @@ class product_product(osv.osv):
         return res
 
     def copy(self, cr, uid, id, default=None, context=None):
-        if not context:
+        if context is None:
             context={}
 
         product = self.read(cr, uid, id, ['name'], context=context)
@@ -637,8 +609,6 @@ class product_packaging(osv.osv):
         if not len(ids):
             return []
         res = []
-        if not context:
-            context = {}
         for pckg in self.browse(cr, uid, ids,context=context):
             p_name = pckg.ean and '[' + pckg.ean + '] ' or ''
             p_name += pckg.ul.name
@@ -672,8 +642,6 @@ class product_supplierinfo(osv.osv):
     _description = "Information about a product supplier"
     def _calc_qty(self, cr, uid, ids, fields, arg, context=None):
         result = {}
-        if not context:
-            context = {}
         product_uom_pool = self.pool.get('product.uom')
         for supplier_info in self.browse(cr, uid, ids, context=context):
             for field in fields:
@@ -710,8 +678,6 @@ class product_supplierinfo(osv.osv):
         'company_id': lambda self,cr,uid,c: self.pool.get('res.company')._company_default_get(cr, uid, 'product.supplierinfo', context=c)
     }
     def _check_uom(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for supplier_info in self.browse(cr, uid, ids, context=context):
             if supplier_info.product_uom and supplier_info.product_uom.category_id.id <> supplier_info.product_id.uom_id.category_id.id:
                 return False
@@ -727,8 +693,6 @@ class product_supplierinfo(osv.osv):
         @param product_id: Id of product.
         @param product_qty: specify quantity to purchase.
         """
-        if not context:
-            context = {}
         if type(supplier_ids) in (int,long,):
             supplier_ids = [supplier_ids]
         res = {}
@@ -779,8 +743,6 @@ pricelist_partnerinfo()
 class res_users(osv.osv):
     _inherit = 'res.users'
     def _get_group(self, cr, uid, context=None):
-        if not context:
-            context = {}
         result = super(res_users, self)._get_group(cr, uid, context=context)
         dataobj = self.pool.get('ir.model.data')
         try:
diff --git a/addons/product/wizard/product_price.py b/addons/product/wizard/product_price.py
index a2c24305e23..5a5327a3f6d 100644
--- a/addons/product/wizard/product_price.py
+++ b/addons/product/wizard/product_price.py
@@ -48,7 +48,7 @@ class product_price_list(osv.osv_memory):
         To get the date and print the report
         @return : return report
         """
-        if not context:
+        if context is None:
             context = {}
         datas = {'ids': context.get('active_ids', [])}
         res = self.read(cr, uid, ids, ['price_list','qty1', 'qty2','qty3','qty4','qty5'], context=context)
diff --git a/addons/product_expiry/product_expiry.py b/addons/product_expiry/product_expiry.py
index ff6728204ee..01ce50dead8 100644
--- a/addons/product_expiry/product_expiry.py
+++ b/addons/product_expiry/product_expiry.py
@@ -54,8 +54,6 @@ class stock_production_lot(osv.osv):
     }
     # Assign dates according to products data
     def create(self, cr, uid, vals, context=None):
-        if not context:
-            context = {}
         newid = super(stock_production_lot, self).create(cr, uid, vals, context=context)
         obj = self.browse(cr, uid, newid, context=context)
         towrite = []
diff --git a/addons/product_margin/wizard/product_margin.py b/addons/product_margin/wizard/product_margin.py
index cdbe70b49bd..d5b502d0545 100644
--- a/addons/product_margin/wizard/product_margin.py
+++ b/addons/product_margin/wizard/product_margin.py
@@ -49,7 +49,7 @@ class product_margin(osv.osv_memory):
 
             @return:
         """
-        if not context:
+        if context is None:
             context = {}
         mod_obj = self.pool.get('ir.model.data')
         result = mod_obj._get_id(cr, uid, 'product', 'product_search_form_view')
diff --git a/addons/project/project.py b/addons/project/project.py
index e432a58b87d..a0eae3022d1 100644
--- a/addons/project/project.py
+++ b/addons/project/project.py
@@ -52,8 +52,6 @@ class project(osv.osv):
     _inherits = {'account.analytic.account': "analytic_account_id"}
 
     def search(self, cr, user, args, offset=0, limit=None, order=None, context=None, count=False):
-        if not context:
-            context = {}
         if user == 1:
             return super(project, self).search(cr, user, args, offset=offset, limit=limit, order=order, context=context, count=count)
         if context and context.has_key('user_prefence') and context['user_prefence']:
@@ -67,8 +65,6 @@ class project(osv.osv):
 
     def _complete_name(self, cr, uid, ids, name, args, context=None):
         res = {}
-        if not context:
-            context = {}
         for m in self.browse(cr, uid, ids, context=context):
             res[m.id] = (m.parent_id and (m.parent_id.name + '/') or '') + m.name
         return res
@@ -77,8 +73,6 @@ class project(osv.osv):
         partner_obj = self.pool.get('res.partner')
         if not part:
             return {'value':{'contact_id': False, 'pricelist_id': False}}
-        if not context:
-            context = {}
         addr = partner_obj.address_get(cr, uid, [part], ['contact'])
         pricelist = partner_obj.read(cr, uid, part, ['property_product_pricelist'], context=context)
         pricelist_id = pricelist.get('property_product_pricelist', False) and pricelist.get('property_product_pricelist')[0] or False
@@ -89,8 +83,6 @@ class project(osv.osv):
         progress = {}
         if not ids:
             return res
-        if not context:
-            context = {}
         cr.execute('''SELECT
                 project_id, sum(planned_hours), sum(total_hours), sum(effective_hours), SUM(remaining_hours)
             FROM
@@ -176,8 +168,6 @@ class project(osv.osv):
 
     # TODO: Why not using a SQL contraints ?
     def _check_dates(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for leave in self.read(cr, uid, ids, ['date_start', 'date'], context=context):
              if leave['date_start'] and leave['date']:
                  if leave['date_start'] > leave['date']:
@@ -189,14 +179,10 @@ class project(osv.osv):
     ]
 
     def set_template(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         res = self.setActive(cr, uid, ids, value=False, context=context)
         return res
 
     def set_done(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         task_obj = self.pool.get('project.task')
         task_ids = task_obj.search(cr, uid, [('project_id', 'in', ids), ('state', 'not in', ('cancelled', 'done'))])
         task_obj.write(cr, uid, task_ids, {'state': 'done', 'date_end':time.strftime('%Y-%m-%d %H:%M:%S'), 'remaining_hours': 0.0})
@@ -207,8 +193,6 @@ class project(osv.osv):
         return True
 
     def set_cancel(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         task_obj = self.pool.get('project.task')
         task_ids = task_obj.search(cr, uid, [('project_id', 'in', ids), ('state', '!=', 'done')])
         task_obj.write(cr, uid, task_ids, {'state': 'cancelled', 'date_end':time.strftime('%Y-%m-%d %H:%M:%S'), 'remaining_hours': 0.0})
@@ -216,20 +200,14 @@ class project(osv.osv):
         return True
 
     def set_pending(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state':'pending'}, context=context)
         return True
 
     def set_open(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state':'open'}, context=context)
         return True
 
     def reset_project(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         res = self.setActive(cr, uid, ids, value=True, context=context)
         for (id, name) in self.name_get(cr, uid, ids):
             message = _("The project '%s' has been opened.") % name
@@ -329,8 +307,6 @@ class task(osv.osv):
     _date_name = "date_start"
 
     def search(self, cr, user, args, offset=0, limit=None, order=None, context=None, count=False):
-        if not context:
-            context = {}
         obj_project = self.pool.get('project.project')
         for domain in args:
             if domain[0] == 'project_id' and (not isinstance(domain[2], str)):
@@ -349,8 +325,6 @@ class task(osv.osv):
     def _hours_get(self, cr, uid, ids, field_names, args, context=None):
         project_obj = self.pool.get('project.project')
         res = {}
-        if not context:
-            context = {}
         cr.execute("SELECT task_id, COALESCE(SUM(hours),0) FROM project_task_work WHERE task_id IN %s GROUP BY task_id",(tuple(ids),))
         hours = dict(cr.fetchall())
         for task in self.browse(cr, uid, ids, context=context):
@@ -381,8 +355,6 @@ class task(osv.osv):
 
     def copy_data(self, cr, uid, id, default={}, context=None):
         default = default or {}
-        if not context:
-            context = {}
         default.update({'work_ids':[], 'date_start': False, 'date_end': False, 'date_deadline': False})
         if not default.get('remaining_hours', False):
             default['remaining_hours'] = float(self.read(cr, uid, id, ['planned_hours'])['planned_hours'])
@@ -393,8 +365,6 @@ class task(osv.osv):
         return super(task, self).copy_data(cr, uid, id, default, context)
 
     def _check_dates(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         task = self.read(cr, uid, ids[0], ['date_start', 'date_end'])
         if task['date_start'] and task['date_end']:
              if task['date_start'] > task['date_end']:
@@ -403,8 +373,6 @@ class task(osv.osv):
 
     def _is_template(self, cr, uid, ids, field_name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         for task in self.browse(cr, uid, ids, context=context):
             res[task.id] = True
             if task.project_id:
@@ -483,8 +451,6 @@ class task(osv.osv):
     _order = "sequence, priority, date_start, id"
 
     def _check_recursion(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         obj_task = self.browse(cr, uid, ids[0], context=context)
         parent_ids = [x.id for x in obj_task.parent_ids]
         children_ids = [x.id for x in obj_task.child_ids]
@@ -517,8 +483,6 @@ class task(osv.osv):
 
     def fields_view_get(self, cr, uid, view_id=None, view_type='form', context=None, toolbar=False, submenu=False):
         users_obj = self.pool.get('res.users')
-        if not context:
-            context = {}
 
         # read uom as admin to avoid access rights issues, e.g. for portal/share users,
         # this should be safe (no context passed to avoid side-effects)
@@ -552,8 +516,6 @@ class task(osv.osv):
         # This action open wizard to send email to partner or project manager after close task.
         project_id = len(ids) and ids[0] or False
         if not project_id: return False
-        if not context:
-            context = {}
         task = self.browse(cr, uid, project_id, context=context)
         project = task.project_id
         res = self.do_close(cr, uid, [project_id], context=context)
@@ -753,8 +715,6 @@ class project_work(osv.osv):
         return super(project_work,self).create(cr, uid, vals, *args, **kwargs)
 
     def write(self, cr, uid, ids, vals, context=None):
-        if not context:
-            context = {}
         if 'hours' in vals and (not vals['hours']):
             vals['hours'] = 0.00
         if 'hours' in vals:
diff --git a/addons/project_caldav/project_caldav.py b/addons/project_caldav/project_caldav.py
index 8deed718793..ada89d35e69 100644
--- a/addons/project_caldav/project_caldav.py
+++ b/addons/project_caldav/project_caldav.py
@@ -57,9 +57,6 @@ class project_task(osv.osv):
         @return: Dictionary value which open Project Task form.
         """
 
-        if not context:
-            context = {}
-
         data_pool = self.pool.get('ir.model.data')
         value = {}
         task_form_id = data_pool.get_object(cr, uid, 'project', 'view_task_form2')
@@ -82,8 +79,6 @@ class project_task(osv.osv):
 
 
     def import_cal(self, cr, uid, data, data_id=None, context=None):
-        if not context:
-            context = {}
         todo_obj = self.pool.get('basic.calendar.todo')
         vals = todo_obj.import_cal(cr, uid, data, context=context)
         return self.check_import(cr, uid, vals, context=context)
diff --git a/addons/project_issue/project_issue.py b/addons/project_issue/project_issue.py
index 17624502535..9e8c5aa7863 100644
--- a/addons/project_issue/project_issue.py
+++ b/addons/project_issue/project_issue.py
@@ -231,8 +231,6 @@ class project_issue(crm.crm_case, osv.osv):
     }
 
     def _get_project(self, cr, uid, context=None):
-        if not context:
-            context = {}
         user = self.pool.get('res.users').browse(cr, uid, uid, context=context)
         if user.context_project_id:
             return user.context_project_id.id
@@ -302,8 +300,6 @@ class project_issue(crm.crm_case, osv.osv):
 
 
     def _convert(self, cr, uid, ids, xml_id, context=None):
-        if not context:
-            context = {}
         data_obj = self.pool.get('ir.model.data')
         id2 = data_obj._get_id(cr, uid, 'project_issue', xml_id)
         categ_id = False
@@ -314,13 +310,9 @@ class project_issue(crm.crm_case, osv.osv):
         return True
 
     def convert_to_feature(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         return self._convert(cr, uid, ids, 'feature_request_categ', context=context)
 
     def convert_to_bug(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         return self._convert(cr, uid, ids, 'bug_categ', context=context)
 
     def next_type(self, cr, uid, ids, *args):
@@ -386,8 +378,7 @@ class project_issue(crm.crm_case, osv.osv):
         @param cr: the current row, from the database cursor,
         @param uid: the current user’s ID for security checks
         """
-        if not context:
-            context = {}
+        if context is None: context = {}
         mailgate_pool = self.pool.get('email.server.tools')
 
         subject = msg.get('subject') or _('No Title')
@@ -475,8 +466,6 @@ class project_issue(crm.crm_case, osv.osv):
         return True
 
     def copy(self, cr, uid, id, default=None, context=None):
-        if not context:
-            context={}
         issue = self.read(cr, uid, id, ['name'], context=context)
         if not default:
             default = {}
@@ -496,8 +485,6 @@ class project(osv.osv):
     }
 
     def _check_escalation(self, cr, uid, ids, context=None):
-         if not context:
-            context = {}
          project_obj = self.browse(cr, uid, ids[0], context=context)
          if project_obj.project_escalation_id:
              if project_obj.project_escalation_id.id == project_obj.id:
diff --git a/addons/project_long_term/project_long_term.py b/addons/project_long_term/project_long_term.py
index 6d26f0dd009..7094eb80512 100644
--- a/addons/project_long_term/project_long_term.py
+++ b/addons/project_long_term/project_long_term.py
@@ -70,24 +70,18 @@ class project_phase(osv.osv):
          return True
 
     def _check_dates(self, cr, uid, ids, context=None):
-         if not context:
-            context = {}
          for phase in self.read(cr, uid, ids, ['date_start', 'date_end'], context=context):
              if phase['date_start'] and phase['date_end'] and phase['date_start'] > phase['date_end']:
                  return False
          return True
 
     def _check_constraint_start(self, cr, uid, ids, context=None):
-         if not context:
-            context = {}
          phase = self.read(cr, uid, ids[0], ['date_start', 'constraint_date_start'], context=context)
          if phase['date_start'] and phase['constraint_date_start'] and phase['date_start'] < phase['constraint_date_start']:
              return False
          return True
 
     def _check_constraint_end(self, cr, uid, ids, context=None):
-         if not context:
-            context = {}
          phase = self.read(cr, uid, ids[0], ['date_end', 'constraint_date_end'], context=context)
          if phase['date_end'] and phase['constraint_date_end'] and phase['date_end'] > phase['constraint_date_end']:
              return False
@@ -102,8 +96,6 @@ class project_phase(osv.osv):
         res = {}
         if not ids:
             return res
-        if not context:
-            context = {}
         for phase in self.browse(cr, uid, ids, context=context):
             tot = 0.0
             for task in phase.task_ids:
@@ -145,8 +137,6 @@ class project_phase(osv.osv):
 
     def onchange_project(self, cr, uid, ids, project, context=None):
         result = {}
-        if not context:
-            context = {}
         result['date_start'] = False
         project_obj = self.pool.get('project.project')
         if project:
@@ -156,8 +146,6 @@ class project_phase(osv.osv):
 
     def onchange_days(self, cr, uid, ids, project, context=None):
         result = {}
-        if not context:
-            context = {}
         for id in ids:
             project_id = self.browse(cr, uid, id, context=context)
             newdate = datetime.strptime(project_id.date_start, '%Y-%m-%d') + relativedelta(days=project_id.duration or 0.0)
@@ -410,8 +398,6 @@ class project_resource_allocation(osv.osv):
 
     def get_name(self, cr, uid, ids, field_name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         for allocation in self.browse(cr, uid, ids, context=context):
             name = allocation.phase_id.name
             name += ' (%s%%)' %(allocation.useability)
diff --git a/addons/project_long_term/wizard/project_compute_phases.py b/addons/project_long_term/wizard/project_compute_phases.py
index f533a496810..ade1da5c9d9 100644
--- a/addons/project_long_term/wizard/project_compute_phases.py
+++ b/addons/project_long_term/wizard/project_compute_phases.py
@@ -37,8 +37,6 @@ class project_compute_phases(osv.osv_memory):
     }
 
     def check_selection(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         return self.compute_date(cr, uid, ids, context=context)
 
     
diff --git a/addons/project_mailgate/project_mailgate.py b/addons/project_mailgate/project_mailgate.py
index 8e41aca42aa..64bb8c2dc69 100644
--- a/addons/project_mailgate/project_mailgate.py
+++ b/addons/project_mailgate/project_mailgate.py
@@ -38,8 +38,6 @@ class project_tasks(osv.osv):
 #        @param cr: the current row, from the database cursor,
 #        @param uid: the current user’s ID for security checks
 #        """
-        if not context:
-            context = {}
         mailgate_obj = self.pool.get('email.server.tools')
         subject = msg.get('subject')
         body = msg.get('body')
@@ -97,8 +95,6 @@ class project_tasks(osv.osv):
 
     def message_followers(self, cr, uid, ids, context=None):
         res = []
-        if not context:
-            context = {}
         if isinstance(ids, (str, int, long)):
             select = [ids]
         else:
diff --git a/addons/project_messages/project_messages.py b/addons/project_messages/project_messages.py
index 9d1f162ef82..93f83d62f4a 100644
--- a/addons/project_messages/project_messages.py
+++ b/addons/project_messages/project_messages.py
@@ -41,8 +41,6 @@ class messages(osv.osv):
     def search(self, cr, uid, args, offset=0, limit=None, order=None, context=None, count=False):
         # return messages by current user, for current user or for all users
         # return all messages if current user is administrator  
-        if not context:
-            context = {}
         if uid != 1:
             args.extend(['|',('from_id', 'in', [uid,]),('to_id', 'in', [uid, False])])
         return super(messages, self).search(cr, uid, args, offset, limit,
diff --git a/addons/project_mrp/project_procurement.py b/addons/project_mrp/project_procurement.py
index 1350573791d..cb2b2f8d6a0 100644
--- a/addons/project_mrp/project_procurement.py
+++ b/addons/project_mrp/project_procurement.py
@@ -30,8 +30,6 @@ class procurement_order(osv.osv):
         'task_id': fields.many2one('project.task', 'Task')
     }
     def check_produce_service(self, cr, uid, procurement, context=None):
-        if not context:
-            context = {}
         return True
 
     def action_produce_assign_service(self, cr, uid, ids, context=None):
diff --git a/addons/project_planning/project_planning.py b/addons/project_planning/project_planning.py
index b8a44ab1c05..aefceedd64b 100644
--- a/addons/project_planning/project_planning.py
+++ b/addons/project_planning/project_planning.py
@@ -30,8 +30,6 @@ import tools
 
 class one2many_mod3(fields.one2many):
     def get(self, cr, obj, ids, name, user=None, offset=0, context=None, values=None):
-        if not context:
-            context = context
         res = {}
         for obj in obj.browse(cr, user, ids, context=context):
             res[obj.id] = []
@@ -82,8 +80,6 @@ class report_account_analytic_planning(osv.osv):
 
     def _get_total_planned(self, cr, uid, ids, name, args, context=None):
         result = {}
-        if not context:
-            context = {}
         for plan in self.browse(cr, uid, ids, context=context):
             plan_hrs=0.0
             for p in plan.planning_user_ids:
@@ -95,8 +91,6 @@ class report_account_analytic_planning(osv.osv):
 
     def _get_total_free(self, cr, uid, ids, name, args, context=None):
         result = {}
-        if not context:
-            context = {}
         for plan in self.browse(cr, uid, ids, context=context):
             total_free = 0.0
             for p in plan.planning_user_ids:
@@ -248,7 +242,7 @@ class project_task(osv.osv):
     }
 
     def search(self, cr, user, args, offset=0, limit=None, order=None, context=None, count=False):
-        if not context:
+        if context is None:
             context = {}
         if not context.get('planning', False):
             return super(project_task,self).search(cr, user, args, offset, limit, order, context)
diff --git a/addons/project_scrum/project_scrum.py b/addons/project_scrum/project_scrum.py
index 451593e30f7..981add11800 100644
--- a/addons/project_scrum/project_scrum.py
+++ b/addons/project_scrum/project_scrum.py
@@ -159,8 +159,6 @@ class project_scrum_product_backlog(osv.osv):
     def name_search(self, cr, uid, name, args=None, operator='ilike', context=None, limit=100):
         if not args:
             args=[]
-        if not context:
-            context={}
         if name:
             match = re.match('^S\(([0-9]+)\)$', name)
             if match:
diff --git a/addons/project_scrum/wizard/project_scrum_email.py b/addons/project_scrum/wizard/project_scrum_email.py
index ee1edfd37e7..3fca16e555f 100644
--- a/addons/project_scrum/wizard/project_scrum_email.py
+++ b/addons/project_scrum/wizard/project_scrum_email.py
@@ -38,7 +38,7 @@ class project_scrum_email(osv.osv_memory):
 
         @return : default values of fields.
         """
-        if not context:
+        if context is None:
             context = {}
         meeting_pool = self.pool.get('project.scrum.meeting')
         record_ids = context and context.get('active_ids', []) or []
diff --git a/addons/purchase/purchase.py b/addons/purchase/purchase.py
index a4e250861bc..101b7dbac8f 100644
--- a/addons/purchase/purchase.py
+++ b/addons/purchase/purchase.py
@@ -45,8 +45,6 @@ class purchase_order(osv.osv):
 
     def _amount_all(self, cr, uid, ids, field_name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         cur_obj=self.pool.get('res.currency')
         for order in self.browse(cr, uid, ids, context=context):
             res[order.id] = {
@@ -67,8 +65,6 @@ class purchase_order(osv.osv):
 
     def _set_minimum_planned_date(self, cr, uid, ids, name, value, arg, context=None):
         if not value: return False
-        if not context:
-            context = {}
         if type(ids)!=type([]):
             ids=[ids]
         for po in self.browse(cr, uid, ids, context=context):
@@ -81,8 +77,6 @@ class purchase_order(osv.osv):
 
     def _minimum_planned_date(self, cr, uid, ids, field_name, arg, context=None):
         res={}
-        if not context:
-            context = {}
         purchase_obj=self.browse(cr, uid, ids, context=context)
         for purchase in purchase_obj:
             res[purchase.id] = time.strftime('%Y-%m-%d %H:%M:%S')
@@ -96,8 +90,6 @@ class purchase_order(osv.osv):
 
     def _invoiced_rate(self, cursor, user, ids, name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         for purchase in self.browse(cursor, user, ids, context=context):
             tot = 0.0
             if purchase.invoice_id and purchase.invoice_id.state not in ('draft','cancel'):
@@ -110,8 +102,6 @@ class purchase_order(osv.osv):
 
     def _shipped_rate(self, cr, uid, ids, name, arg, context=None):
         if not ids: return {}
-        if not context:
-            context = {}
         res = {}
         for id in ids:
             res[id] = [0.0,0.0]
@@ -140,16 +130,12 @@ class purchase_order(osv.osv):
 
     def _get_order(self, cr, uid, ids, context=None):
         result = {}
-        if not context:
-            context = {}
         for line in self.pool.get('purchase.order.line').browse(cr, uid, ids, context=context):
             result[line.order_id.id] = True
         return result.keys()
 
     def _invoiced(self, cursor, user, ids, name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         for purchase in self.browse(cursor, user, ids, context=context):
             if purchase.invoice_id.reconciled:
                 res[purchase.id] = purchase.invoice_id.reconciled
@@ -237,8 +223,6 @@ class purchase_order(osv.osv):
     _order = "name desc"
 
     def unlink(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         purchase_orders = self.read(cr, uid, ids, ['state'])
         unlink_ids = []
         for s in purchase_orders:
@@ -288,8 +272,6 @@ class purchase_order(osv.osv):
     #TODO: implement messages system
     def wkf_confirm_order(self, cr, uid, ids, context=None):
         todo = []
-        if not context:
-            context = {}
         for po in self.browse(cr, uid, ids, context=context):
             if not po.order_line:
                 raise osv.except_osv(_('Error !'),_('You can not confirm purchase order without Purchase Order Lines.'))
@@ -405,8 +387,6 @@ class purchase_order(osv.osv):
         return False
 
     def action_cancel(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for purchase in self.browse(cr, uid, ids, context=context):
             for pick in purchase.picking_ids:
                 if pick.state not in ('draft','cancel'):
@@ -513,8 +493,6 @@ class purchase_order(osv.osv):
          @return: new purchase order id
 
         """
-        if not context:
-            context = {}
         wf_service = netsvc.LocalService("workflow")
         def make_key(br, fields):
             list_key = []
@@ -608,8 +586,6 @@ purchase_order()
 class purchase_order_line(osv.osv):
     def _amount_line(self, cr, uid, ids, prop, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         cur_obj=self.pool.get('res.currency')
         tax_obj = self.pool.get('account.tax')
         for line in self.browse(cr, uid, ids, context=context):
@@ -656,8 +632,6 @@ class purchase_order_line(osv.osv):
     def copy_data(self, cr, uid, id, default=None, context=None):
         if not default:
             default = {}
-        if not context:
-            context = {}
         default.update({'state':'draft', 'move_ids':[],'invoiced':0,'invoice_lines':[]})
         return super(purchase_order_line, self).copy_data(cr, uid, id, default, context)
 
@@ -735,8 +709,6 @@ class purchase_order_line(osv.osv):
         return res
 
     def action_confirm(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state': 'confirmed'}, context=context)
         return True
 
@@ -752,8 +724,6 @@ class procurement_order(osv.osv):
         """ This is action which call from workflow to assign purchase order to procurements
         @return: True
         """
-        if not context:
-            context = {}
         res = self.make_po(cr, uid, ids, context=context)
         res = res.values()
         return len(res) and res[0] or 0 #TO CHECK: why workflow is generated error if return not integer value
@@ -763,7 +733,7 @@ class procurement_order(osv.osv):
         @return: New created Purchase Orders procurement wise
         """
         res = {}
-        if not context:
+        if context is None:
             context = {}
         company = self.pool.get('res.users').browse(cr, uid, uid, context=context).company_id
         partner_obj = self.pool.get('res.partner')
diff --git a/addons/purchase/stock.py b/addons/purchase/stock.py
index ca53b3df762..6ed3839fe9e 100644
--- a/addons/purchase/stock.py
+++ b/addons/purchase/stock.py
@@ -35,8 +35,6 @@ class stock_move(osv.osv):
         on the purchase order in case the valuation data was not directly specified during picking
         confirmation.
         """
-        if not context:
-            context = {}
         reference_amount, reference_currency_id = super(stock_move, self)._get_reference_accounting_values_for_valuation(cr, uid, move, context=context)
         if move.product_id.cost_method != 'average' or not move.price_unit:
             # no average price costing or cost not specified during picking validation, we will 
@@ -120,7 +118,7 @@ class stock_partial_picking(osv.osv_memory):
         @param context: A standard dictionary
         @return: A dictionary which of fields with values.
         """
-        if not context:
+        if context is None:
             context = {}
         pick_obj = self.pool.get('stock.picking')
         res = super(stock_partial_picking, self).default_get(cr, uid, fields, context=context)
@@ -146,7 +144,7 @@ class stock_partial_move(osv.osv_memory):
         @param context: A standard dictionary
         @return: A dictionary which of fields with values.
         """
-        if not context:
+        if context is None:
             context = {}
         res = super(stock_partial_move, self).default_get(cr, uid, fields, context=context)
         move_obj = self.pool.get('stock.move')
diff --git a/addons/purchase/wizard/purchase_order_group.py b/addons/purchase/wizard/purchase_order_group.py
index ce631ec3e8b..2496044a45e 100644
--- a/addons/purchase/wizard/purchase_order_group.py
+++ b/addons/purchase/wizard/purchase_order_group.py
@@ -40,7 +40,7 @@ class purchase_order_group(osv.osv_memory):
          @param context: A standard dictionary 
          @return: New arch of view.
         """
-        if not context:
+        if context is None:
             context={}
         res = super(purchase_order_group, self).fields_view_get(cr, uid, view_id=view_id, view_type=view_type, context=context, toolbar=toolbar,submenu=False)
         if context.get('active_model','') == 'purchase.order' and len(context['active_ids']) < 2:
@@ -62,7 +62,7 @@ class purchase_order_group(osv.osv_memory):
         """
         order_obj = self.pool.get('purchase.order')
         mod_obj =self.pool.get('ir.model.data')
-        if not context:
+        if context is None:
             context = {}
         result = mod_obj._get_id(cr, uid, 'purchase', 'view_purchase_order_filter')
         id = mod_obj.read(cr, uid, result, ['res_id'])
diff --git a/addons/purchase_requisition/purchase_requisition.py b/addons/purchase_requisition/purchase_requisition.py
index 881e4819fcb..615312851fe 100644
--- a/addons/purchase_requisition/purchase_requisition.py
+++ b/addons/purchase_requisition/purchase_requisition.py
@@ -55,8 +55,6 @@ class purchase_requisition(osv.osv):
     def copy(self, cr, uid, id, default=None, context=None):
         if not default:
             default = {}
-        if not context:
-            context = {}
         default.update({
             'state':'draft',
             'purchase_ids':[],
@@ -65,8 +63,6 @@ class purchase_requisition(osv.osv):
         return super(purchase_requisition, self).copy(cr, uid, id, default, context)
     def tender_cancel(self, cr, uid, ids, context=None):
         purchase_order_obj = self.pool.get('purchase.order')
-        if not context:
-            context = {}
         for purchase in self.browse(cr, uid, ids, context=context):
             for purchase_id in purchase.purchase_ids:
                 if str(purchase_id.state) in('draft','wait'):
@@ -75,20 +71,14 @@ class purchase_requisition(osv.osv):
         return True
 
     def tender_in_progress(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state':'in_progress'} ,context=context)
         return True
 
     def tender_reset(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state': 'draft'})
         return True
 
     def tender_done(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state':'done', 'date_end':time.strftime('%Y-%m-%d %H:%M:%S')}, context=context)
         return True
 
@@ -116,8 +106,6 @@ class purchase_requisition_line(osv.osv):
         @return:  Dictionary of changed values
         """
         value = {'product_uom_id': ''}
-        if not context:
-            context = {}
         if product_id:
             prod = self.pool.get('product.product').browse(cr, uid, [product_id], context=context)[0]
             value = {'product_uom_id': prod.uom_id.id,'product_qty':1.0}
@@ -134,8 +122,6 @@ class purchase_order(osv.osv):
         'requisition_id' : fields.many2one('purchase.requisition','Purchase Requisition')
     }
     def wkf_confirm_order(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         res = super(purchase_order, self).wkf_confirm_order(cr, uid, ids, context=context)
         proc_obj=self.pool.get('procurement.order')
         for po in self.browse(cr, uid, ids, context=context):
@@ -172,8 +158,6 @@ class procurement_order(osv.osv):
     }
     def make_po(self, cr, uid, ids, context=None):
         sequence_obj = self.pool.get('ir.sequence')
-        if not context:
-            context = {}
         res = super(procurement_order, self).make_po(cr, uid, ids, context=context)
         for proc_id, po_id in res.items():
             procurement = self.browse(cr, uid, proc_id, context=context)
diff --git a/addons/purchase_requisition/wizard/purchase_requisition_partner.py b/addons/purchase_requisition/wizard/purchase_requisition_partner.py
index 33cac7891a7..d62aad1e695 100644
--- a/addons/purchase_requisition/wizard/purchase_requisition_partner.py
+++ b/addons/purchase_requisition/wizard/purchase_requisition_partner.py
@@ -34,7 +34,7 @@ class purchase_requisition_partner(osv.osv_memory):
     }
 
     def view_init(self, cr, uid, fields_list, context=None):
-        if not context:
+        if context is None:
             context = {}
         res = super(purchase_requisition_partner, self).view_init(cr, uid, fields_list, context=context)
         record_id = context and context.get('active_id', False) or False
@@ -62,7 +62,7 @@ class purchase_requisition_partner(osv.osv_memory):
              @return: {}
 
         """
-        if not context:
+        if context is None:
             context = {}
         record_ids = context and context.get('active_ids', False)
         if record_ids:
diff --git a/addons/report_webkit/ir_report.py b/addons/report_webkit/ir_report.py
index cffd3d89659..b3155b25430 100644
--- a/addons/report_webkit/ir_report.py
+++ b/addons/report_webkit/ir_report.py
@@ -59,8 +59,6 @@ class ReportXML(osv.osv):
 
     def unlink(self, cursor, user, ids, context=None):
         """Delete report and unregister it"""
-        if not context:
-            context = {}
         trans_obj = self.pool.get('ir.translation')
         trans_ids = trans_obj.search(
             cursor,
@@ -83,8 +81,6 @@ class ReportXML(osv.osv):
 
     def create(self, cursor, user, vals, context=None):
         "Create report and register it"
-        if not context:
-            context = {}
         res = super(ReportXML, self).create(cursor, user, vals, context)
         if vals.get('report_type','') == 'webkit':
             # I really look forward to virtual functions :S
@@ -99,8 +95,6 @@ class ReportXML(osv.osv):
         "Edit report and manage it registration"
         if isinstance(ids, (int, long)):
             ids = [ids,]
-        if not context:
-            context = {}
         for rep in self.browse(cr, uid, ids, context=context):
             if rep.report_type != 'webkit':
                 continue
diff --git a/addons/report_webkit/webkit_report.py b/addons/report_webkit/webkit_report.py
index 48b0fb4b26b..c95a9ce5e2e 100644
--- a/addons/report_webkit/webkit_report.py
+++ b/addons/report_webkit/webkit_report.py
@@ -320,8 +320,6 @@ class WebKitParser(report_sxw):
     def create(self, cursor, uid, ids, data, context=None):
         """We override the create function in order to handle generator
            Code taken from report openoffice. Thanks guys :) """
-        if not context:
-            context = {}
         pool = pooler.get_pool(cursor.dbname)
         ir_obj = pool.get('ir.actions.report.xml')
         report_xml_ids = ir_obj.search(cursor, uid,
diff --git a/addons/resource/resource.py b/addons/resource/resource.py
index 0e8ebc692bf..2221c4279c8 100644
--- a/addons/resource/resource.py
+++ b/addons/resource/resource.py
@@ -242,8 +242,6 @@ class resource_resource(osv.osv):
     def copy(self, cr, uid, id, default=None, context=None):
         if default is None:
             default = {}
-        if not context:
-            context = {}
         if not default.get('name', False):
             default['name'] = self.browse(cr, uid, id, context=context).name + _(' (copy)')
         return super(resource_resource, self).copy(cr, uid, id, default, context)
@@ -367,8 +365,6 @@ class resource_calendar_leaves(osv.osv):
     }
 
     def check_dates(self, cr, uid, ids, context=None):
-         if not context:
-            context = {}
          leave = self.read(cr, uid, ids[0], ['date_from', 'date_to'])
          if leave['date_from'] and leave['date_to']:
              if leave['date_from'] > leave['date_to']:
@@ -381,8 +377,6 @@ class resource_calendar_leaves(osv.osv):
 
     def onchange_resource(self,cr, uid, ids, resource, context=None):
         result = {}
-        if not context:
-            context = {}
         if resource:
             resource_pool = self.pool.get('resource.resource')
             result['calendar_id'] = resource_pool.browse(cr, uid, resource, context=context).calendar_id.id
diff --git a/addons/sale/stock.py b/addons/sale/stock.py
index 90e01a8dc50..7f3160c4fa7 100644
--- a/addons/sale/stock.py
+++ b/addons/sale/stock.py
@@ -28,8 +28,6 @@ class stock_move(osv.osv):
     }
 
     def _create_chained_picking(self, cr, uid, pick_name, picking, ptype, move, context=None):
-        if not context:
-            context = {}
         res = super(stock_move, self)._create_chained_picking(cr, uid, pick_name, picking, ptype, move, context=context)
         if picking.sale_id:
             self.pool.get('stock.picking').write(cr, uid, [res], {'sale_id': picking.sale_id.id})
@@ -184,8 +182,6 @@ class stock_picking(osv.osv):
         return result
 
     def action_cancel(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         res = super(stock_picking, self).action_cancel(cr, uid, ids, context=context)
         for pick in self.browse(cr, uid, ids, context=context):
             call_ship_end = True
diff --git a/addons/sale/wizard/sale_make_invoice.py b/addons/sale/wizard/sale_make_invoice.py
index 7527499859d..f414c2475d5 100644
--- a/addons/sale/wizard/sale_make_invoice.py
+++ b/addons/sale/wizard/sale_make_invoice.py
@@ -46,7 +46,7 @@ class sale_make_invoice(osv.osv_memory):
         order_obj = self.pool.get('sale.order')
         mod_obj = self.pool.get('ir.model.data')
         newinv = []
-        if not context:
+        if context is None:
             context = {}
         data = self.read(cr, uid, ids)[0]
         order_obj.action_invoice_create(cr, uid, context.get(('active_ids'), []), data['grouped'], date_inv = data['invoice_date'])
diff --git a/addons/sale/wizard/sale_make_invoice_advance.py b/addons/sale/wizard/sale_make_invoice_advance.py
index 3d4c801379e..29e87259903 100644
--- a/addons/sale/wizard/sale_make_invoice_advance.py
+++ b/addons/sale/wizard/sale_make_invoice_advance.py
@@ -51,7 +51,7 @@ class sale_advance_payment_inv(osv.osv_memory):
         obj_sale = self.pool.get('sale.order')
         obj_lines = self.pool.get('account.invoice.line')
         inv_obj = self.pool.get('account.invoice')
-        if not context:
+        if context is None:
             context = {}
 
         for sale_adv_obj in self.browse(cr, uid, ids, context=context):
diff --git a/addons/sale_crm/wizard/crm_make_sale.py b/addons/sale_crm/wizard/crm_make_sale.py
index 0c72c3205cd..7ee996dfd75 100644
--- a/addons/sale_crm/wizard/crm_make_sale.py
+++ b/addons/sale_crm/wizard/crm_make_sale.py
@@ -39,7 +39,7 @@ class crm_make_sale(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return: default value of partner_id field.
         """
-        if not context:
+        if context is None:
             context = {}
 
         lead_obj = self.pool.get('crm.lead')
@@ -65,7 +65,7 @@ class crm_make_sale(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return: Dictionary value of created sale order.
         """
-        if not context:
+        if context is None:
             context = {}
 
         case_obj = self.pool.get('crm.lead')
diff --git a/addons/sale_layout/sale_layout.py b/addons/sale_layout/sale_layout.py
index fc6ca6be1a6..cd396fc785b 100755
--- a/addons/sale_layout/sale_layout.py
+++ b/addons/sale_layout/sale_layout.py
@@ -36,8 +36,6 @@ class sale_order_line(osv.osv):
     def invoice_line_create(self, cr, uid, ids, context=None):
         new_ids = []
         list_seq = []
-        if not context:
-            context = {}
         for line in self.browse(cr, uid, ids, context=context):
             if line.layout_type == 'article':
                 new_ids.append(line.id)
@@ -80,8 +78,6 @@ class sale_order_line(osv.osv):
         return {}
 
     def create(self, cr, user, vals, context=None):
-        if not context:
-            context = {}
         if vals.has_key('layout_type'):
             if vals['layout_type'] == 'line':
                 vals['name'] = ' '
@@ -92,8 +88,6 @@ class sale_order_line(osv.osv):
         return super(sale_order_line, self).create(cr, user, vals, context)
 
     def write(self, cr, user, ids, vals, context=None):
-        if not context:
-            context = {}
         if vals.has_key('layout_type'):
             if vals['layout_type'] == 'line':
                 vals['name'] = ' '
@@ -102,8 +96,6 @@ class sale_order_line(osv.osv):
         return super(sale_order_line, self).write(cr, user, ids, vals, context)
 
     def copy(self, cr, uid, id, default=None, context=None):
-        if not context:
-            context = {}
         if default is None:
             default = {}
         default['layout_type'] = self.browse(cr, uid, id, context=context).layout_type
@@ -135,8 +127,6 @@ sale_order_line()
 
 class one2many_mod2(fields.one2many):
     def get(self, cr, obj, ids, name, user=None, offset=0, context=None, values=None):
-        if not context:
-            context = {}
         if not values:
             values = {}
         res = {}
diff --git a/addons/sale_margin/sale_margin.py b/addons/sale_margin/sale_margin.py
index 527c388ec26..fdf7eaf69e4 100644
--- a/addons/sale_margin/sale_margin.py
+++ b/addons/sale_margin/sale_margin.py
@@ -36,8 +36,6 @@ class sale_order_line(osv.osv):
 
     def _product_margin(self, cr, uid, ids, field_name, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         for line in self.browse(cr, uid, ids, context=context):
             res[line.id] = 0
             if line.product_id:
@@ -59,8 +57,6 @@ class sale_order(osv.osv):
 
     def _product_margin(self, cr, uid, ids, field_name, arg, context=None):
         result = {}
-        if not context:
-            context = {}
         for sale in self.browse(cr, uid, ids, context=context):
             result[sale.id] = 0.0
             for line in sale.order_line:
@@ -99,16 +95,12 @@ class account_invoice_line(osv.osv):
         'cost_price': fields.float('Cost Price', digits=(16, 2)),
     }
     def write(self, cr, uid, ids, vals, context=None):
-        if not context:
-            context = {}
         if vals.get('product_id', False):
             res = self.pool.get('product.product').read(cr, uid, [vals['product_id']], ['standard_price'])
             vals['cost_price'] = res[0]['standard_price']
         return super(account_invoice_line, self).write(cr, uid, ids, vals, context)
 
     def create(self, cr, uid, vals, context=None):
-        if not context:
-            context = {}
         if vals.get('product_id',False):
             res = self.pool.get('product.product').read(cr, uid, [vals['product_id']], ['standard_price'])
             vals['cost_price'] = res[0]['standard_price']
diff --git a/addons/sale_order_dates/sale_order_dates.py b/addons/sale_order_dates/sale_order_dates.py
index a13186a8469..d5d3eeca405 100644
--- a/addons/sale_order_dates/sale_order_dates.py
+++ b/addons/sale_order_dates/sale_order_dates.py
@@ -30,8 +30,6 @@ class sale_order_dates(osv.osv):
     def _get_effective_date(self, cr, uid, ids, name, arg, context=None):
         res = {}
         dates_list = []
-        if not context:
-            context = {}
         for order in self.browse(cr, uid, ids, context=context):
             dates_list = []
             for pick in order.picking_ids:
@@ -45,8 +43,6 @@ class sale_order_dates(osv.osv):
     def _get_commitment_date(self, cr, uid, ids, name, arg, context=None):
         res = {}
         dates_list = []
-        if not context:
-            context = {}
         for order in self.browse(cr, uid, ids, context=context):
             dates_list = []
             for line in order.order_line:
diff --git a/addons/stock/product.py b/addons/stock/product.py
index df47ca29d16..0b6cb381fb7 100644
--- a/addons/stock/product.py
+++ b/addons/stock/product.py
@@ -63,7 +63,7 @@ class product_product(osv.osv):
         location_obj = self.pool.get('stock.location')
         move_obj = self.pool.get('account.move')
         move_line_obj = self.pool.get('account.move.line')
-        if not context:
+        if context is None:
             context = {}
 
         new_price = datas.get('new_price', 0.0)
diff --git a/addons/stock/stock.py b/addons/stock/stock.py
index fd12bc133de..0935af68a92 100644
--- a/addons/stock/stock.py
+++ b/addons/stock/stock.py
@@ -487,8 +487,6 @@ class stock_tracking(osv.osv):
     def name_search(self, cr, user, name, args=None, operator='ilike', context=None, limit=100):
         if not args:
             args = []
-        if not context:
-            context = {}
         ids = self.search(cr, user, [('serial', '=', name)]+ args, limit=limit, context=context)
         ids += self.search(cr, user, [('name', operator, name)]+ args, limit=limit, context=context)
         return self.name_get(cr, user, ids, context)
@@ -534,8 +532,6 @@ class stock_picking(osv.osv):
             return False
         if isinstance(ids, (int, long)):
             ids = [ids]
-        if not context:
-            context = {}
         for pick in self.browse(cr, uid, ids, context=context):
             sql_str = """update stock_move set
                     date='%s'
@@ -558,8 +554,6 @@ class stock_picking(osv.osv):
             return False
         if isinstance(ids, (int, long)):
             ids = [ids]
-        if not context:
-            context = {}
         for pick in self.browse(cr, uid, ids, context=context):
             sql_str = """update stock_move set
                     date='%s'
@@ -595,8 +589,6 @@ class stock_picking(osv.osv):
         return res
 
     def create(self, cr, user, vals, context=None):
-        if not context:
-            context = {}
         if ('name' not in vals) or (vals.get('name')=='/'):
             seq_obj_name =  'stock.picking.' + vals['type']
             vals['name'] = self.pool.get('ir.sequence').get(cr, user, seq_obj_name)
@@ -656,8 +648,6 @@ class stock_picking(osv.osv):
         'company_id': lambda self, cr, uid, c: self.pool.get('res.company')._company_default_get(cr, uid, 'stock.picking', context=c)
     }
     def action_process(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         return {
             'name':_("Products to Process"),
             'view_mode': 'form',
@@ -678,8 +668,6 @@ class stock_picking(osv.osv):
         if default is None:
             default = {}
         default = default.copy()
-        if not context:
-            context = {}
         picking_obj = self.browse(cr, uid, [id], context=context)[0]
         move_obj=self.pool.get('stock.move')
         if ('name' not in default) or (picking_obj.name=='/'):
@@ -706,8 +694,6 @@ class stock_picking(osv.osv):
         """
         self.write(cr, uid, ids, {'state': 'confirmed'})
         todo = []
-        if not context:
-            context = {}
         for picking in self.browse(cr, uid, ids, context=context):
             for r in picking.move_lines:
                 if r.state == 'draft':
@@ -796,8 +782,6 @@ class stock_picking(osv.osv):
         """ Changes picking state to assigned.
         @return: True
         """
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state': 'assigned'})
         self.log_picking(cr, uid, ids, context=context)
         return True
@@ -834,8 +818,6 @@ class stock_picking(osv.osv):
         """ Changes picking state to cancel.
         @return: True
         """
-        if not context:
-            context = {}
         for pick in self.browse(cr, uid, ids, context=context):
             ids2 = [move.id for move in pick.move_lines]
             self.pool.get('stock.move').action_cancel(cr, uid, ids2, context)
@@ -1084,8 +1066,6 @@ class stock_picking(osv.osv):
         @return: True or False
         """
         ok = False
-        if not context:
-            context = {}
         for pick in self.browse(cr, uid, ids, context=context):
             if not pick.move_lines:
                 return True
@@ -1100,8 +1080,6 @@ class stock_picking(osv.osv):
         """ Test whether the move lines are canceled or not.
         @return: True or False
         """
-        if not context:
-            context = {}
         for pick in self.browse(cr, uid, ids, context=context):
             for move in pick.move_lines:
                 if move.state not in ('cancel',):
@@ -1109,8 +1087,6 @@ class stock_picking(osv.osv):
         return True
    
     def allow_cancel(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for pick in self.browse(cr, uid, ids, context=context):
             if not pick.move_lines:
                 return True
@@ -1284,8 +1260,6 @@ class stock_picking(osv.osv):
         @param ids: List of Picking Ids
         @param context: A standard dictionary for contextual values
         """
-        if not context:
-            context = {}
         for pick in self.browse(cr, uid, ids, context=context):
             msg=''
             if pick.auto_picking:
@@ -1335,7 +1309,7 @@ class stock_production_lot(osv.osv):
         """ Gets stock of products for locations
         @return: Dictionary of values
         """
-        if not context:
+        if context is None:
             context = {}
         if 'location_id' not in context:
             locations = self.pool.get('stock.location').search(cr, uid, [('usage', '=', 'internal')], context=context)
@@ -1362,8 +1336,6 @@ class stock_production_lot(osv.osv):
         """ Searches Ids of products
         @return: Ids of locations
         """
-        if not context:
-            context = {}
         locations = self.pool.get('stock.location').search(cr, uid, [('usage', '=', 'internal')])
         cr.execute('''select
                 prodlot_id,
@@ -1407,8 +1379,6 @@ class stock_production_lot(osv.osv):
         @param context: A standard dictionary 
         @return: A dictionary of values
         """
-        if not context:
-            context = {}
         value=self.pool.get('action.traceability').action_traceability(cr,uid,ids,context)
         return value
 stock_production_lot()
@@ -1455,8 +1425,6 @@ class stock_move(osv.osv):
 
     def name_get(self, cr, uid, ids, context=None):
         res = []
-        if not context:
-            context = {}
         for line in self.browse(cr, uid, ids, context=context):
             res.append((line.id, (line.product_id.code or '/')+': '+line.location_id.name+' > '+line.location_dest_id.name))
         return res
@@ -1539,7 +1507,7 @@ class stock_move(osv.osv):
         """ Gets default address of partner for destination location
         @return: Address id or False
         """
-        if not context:
+        if context is None:
             context = {}
         if context.get('move_line', []):
             if context['move_line'][0]:
@@ -1557,7 +1525,7 @@ class stock_move(osv.osv):
         """ Gets default address of partner for source location
         @return: Address id or False
         """
-        if not context:
+        if context is None:
             context = {}
         if context.get('move_line', []):
             try:
@@ -1581,8 +1549,6 @@ class stock_move(osv.osv):
     }
 
     def write(self, cr, uid, ids, vals, context=None):
-        if not context:
-            context = {}
         if uid != 1:
             frozen_fields = set(['product_qty', 'product_uom', 'product_uos_qty', 'product_uos', 'location_id', 'location_dest_id', 'product_id'])
             for move in self.browse(cr, uid, ids, context=context):
@@ -1596,13 +1562,9 @@ class stock_move(osv.osv):
         if default is None:
             default = {}
         default = default.copy()
-        if not context:
-            context = {}
         return super(stock_move, self).copy(cr, uid, id, default, context=context)
 
     def _auto_init(self, cursor, context=None):
-        if not context:
-            context = {}
         res = super(stock_move, self)._auto_init(cursor, context=context)
         cursor.execute('SELECT indexname \
                 FROM pg_indexes \
@@ -1701,8 +1663,6 @@ class stock_move(osv.osv):
         @return: Dictionary containing destination location with chained location type.
         """
         result = {}
-        if not context:
-            context = {}
         for m in moves:
             dest = self.pool.get('stock.location').chained_location_get(
                 cr,
@@ -1735,8 +1695,6 @@ class stock_move(osv.osv):
     def _create_chained_picking(self, cr, uid, pick_name,picking,ptype,move, context=None):
         res_obj = self.pool.get('res.company')
         picking_obj = self.pool.get('stock.picking')
-        if not context:
-            context = {}
         pick_id= picking_obj.create(cr, uid, {
                                 'name': pick_name,
                                 'origin': str(picking.origin or ''),
@@ -1755,8 +1713,6 @@ class stock_move(osv.osv):
         """ Confirms stock move.
         @return: List of ids.
         """
-        if not context:
-            context = {}
         moves = self.browse(cr, uid, ids, context=context)
         self.write(cr, uid, ids, {'state': 'confirmed'})
         res_obj = self.pool.get('res.company')
@@ -1814,8 +1770,6 @@ class stock_move(osv.osv):
         """ Changes the state to assigned.
         @return: True
         """
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state': 'assigned'})
         return True
 
@@ -1823,8 +1777,6 @@ class stock_move(osv.osv):
         """ Changes the state to confirmed.
         @return: True
         """
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state': 'confirmed'})
         return True
 
@@ -1927,8 +1879,6 @@ class stock_move(osv.osv):
         :param context: context dictionary that can explicitly mention the company to consider via the 'force_company' key
         :raise: osv.except_osv() is any mandatory account or journal is not defined.
         """
-        if not context:
-            context = {}
         product_obj=self.pool.get('product.product')
         accounts = product_obj.get_product_accounts(cr, uid, move.product_id.id, context)
         acc_src = accounts['stock_account_input']
@@ -2150,8 +2100,6 @@ class stock_move(osv.osv):
         if quantity <= 0:
             raise osv.except_osv(_('Warning!'), _('Please provide a positive quantity to scrap!'))
         res = []
-        if not context:
-            context = {}
         for move in self.browse(cr, uid, ids, context=context):
             move_qty = move.product_qty
             uos_qty = quantity / move_qty * move.product_uos_qty
@@ -2507,8 +2455,6 @@ class stock_inventory(osv.osv):
         """ Cancels the stock move and change inventory state to draft.
         @return: True
         """
-        if not context:
-            context = {}
         for inv in self.browse(cr, uid, ids, context=context):
             self.pool.get('stock.move').action_cancel(cr, uid, [x.id for x in inv.move_ids], context)
             self.write(cr, uid, [inv.id], {'state': 'draft'})
@@ -2518,8 +2464,6 @@ class stock_inventory(osv.osv):
         """ Cancels both stock move and inventory
         @return: True
         """
-        if not context:
-            context = {}
         for inv in self.browse(cr, uid, ids, context=context):
             self.pool.get('stock.move').action_cancel(cr, uid, [x.id for x in inv.move_ids], context)
             self.write(cr, uid, [inv.id], {'state':'cancel'})
diff --git a/addons/stock/wizard/stock_change_standard_price.py b/addons/stock/wizard/stock_change_standard_price.py
index 1910dd75410..198b067ac79 100644
--- a/addons/stock/wizard/stock_change_standard_price.py
+++ b/addons/stock/wizard/stock_change_standard_price.py
@@ -46,7 +46,7 @@ class change_standard_price(osv.osv_memory):
          @param context: A standard dictionary
          @return: A dictionary which of fields with values.
         """
-        if not context:
+        if context is None:
             context = {}
         product_pool = self.pool.get('product.product')
         product_obj = product_pool.browse(cr, uid, context.get('active_id', False))
@@ -80,7 +80,7 @@ class change_standard_price(osv.osv_memory):
         @param context: A standard dictionary
         @return: Dictionary of values
         """
-        if not context:
+        if context is None:
             context = {}
         product_obj = self.pool.get('product.product').browse(cr, uid, context.get('active_id', False), context=context)
         price = product_obj.standard_price
@@ -100,7 +100,7 @@ class change_standard_price(osv.osv_memory):
         @param context: A standard dictionary
         @return:
         """
-        if not context:
+        if context is None:
             context = {}
         rec_id = context and context.get('active_id', False)
         assert rec_id, _('Active ID is not set in Context')
diff --git a/addons/stock/wizard/stock_fill_inventory.py b/addons/stock/wizard/stock_fill_inventory.py
index c0d3f24281d..fe736e249cd 100644
--- a/addons/stock/wizard/stock_fill_inventory.py
+++ b/addons/stock/wizard/stock_fill_inventory.py
@@ -57,8 +57,8 @@ class stock_fill_inventory(osv.osv_memory):
         @param context: A standard dictionary
         @return:
         """
-        if context==None:
-            context={}        
+        if context is None:
+            context = {}        
         inventory_line_obj = self.pool.get('stock.inventory.line')
         location_obj = self.pool.get('stock.location')
         product_obj = self.pool.get('product.product')
diff --git a/addons/stock/wizard/stock_inventory_line_split.py b/addons/stock/wizard/stock_inventory_line_split.py
index 13804542d66..11a6a2da323 100644
--- a/addons/stock/wizard/stock_inventory_line_split.py
+++ b/addons/stock/wizard/stock_inventory_line_split.py
@@ -39,7 +39,7 @@ class stock_inventory_line_split(osv.osv_memory):
         @param context: A standard dictionary 
         @return: A dictionary which of fields with values. 
         """        
-        if not context:
+        if context is None:
             context = {}
         record_id = context and context.get('active_id',False)
         res = {}
@@ -66,8 +66,6 @@ class stock_inventory_line_split(osv.osv_memory):
         ir_sequence_obj = self.pool.get('ir.sequence')
         line_obj = self.pool.get('stock.inventory.line')
         new_line = []        
-        if not context:
-            context = {}
         for data in self.browse(cr, uid, ids, context=context):
             for inv_line in line_obj.browse(cr, uid, line_ids, context=context):
                 line_qty = inv_line.product_qty
diff --git a/addons/stock/wizard/stock_inventory_merge.py b/addons/stock/wizard/stock_inventory_merge.py
index 02e4d73580e..f5ca234d66f 100644
--- a/addons/stock/wizard/stock_inventory_merge.py
+++ b/addons/stock/wizard/stock_inventory_merge.py
@@ -36,7 +36,7 @@ class stock_inventory_merge(osv.osv_memory):
          @param context: A standard dictionary 
          @return: New arch of view.
         """
-        if not context:
+        if context is None:
             context={}
         res = super(stock_inventory_merge, self).fields_view_get(cr, uid, view_id=view_id, view_type=view_type, context=context, toolbar=toolbar,submenu=False)
         if context.get('active_model','') == 'stock.inventory' and len(context['active_ids']) < 2:
@@ -56,7 +56,7 @@ class stock_inventory_merge(osv.osv_memory):
         invent_obj = self.pool.get('stock.inventory')
         invent_line_obj = self.pool.get('stock.inventory.line')
         invent_lines = {}
-        if not context:
+        if context is None:
             context = {}
         for inventory in invent_obj.browse(cr, uid, context['active_ids'], context=context):
             if inventory.state == "done":
diff --git a/addons/stock/wizard/stock_move.py b/addons/stock/wizard/stock_move.py
index 910164af3bd..038878a6330 100644
--- a/addons/stock/wizard/stock_move.py
+++ b/addons/stock/wizard/stock_move.py
@@ -70,7 +70,7 @@ class stock_move_consume(osv.osv_memory):
         @param context: A standard dictionary
         @return: default values of fields
         """
-        if not context:
+        if context is None:
             context = {}
         res = super(stock_move_consume, self).default_get(cr, uid, fields, context=context)
         move = self.pool.get('stock.move').browse(cr, uid, context['active_id'], context=context)
@@ -94,7 +94,7 @@ class stock_move_consume(osv.osv_memory):
         @param context: A standard dictionary
         @return:
         """
-        if not context:
+        if context is None:
             context = {}
         move_obj = self.pool.get('stock.move')
         move_ids = context['active_ids']
@@ -125,7 +125,7 @@ class stock_move_scrap(osv.osv_memory):
         @param context: A standard dictionary
         @return: default values of fields
         """
-        if not context:
+        if context is None:
             context = {}
         res = super(stock_move_consume, self).default_get(cr, uid, fields, context=context)
         move = self.pool.get('stock.move').browse(cr, uid, context['active_id'], context=context)
@@ -155,7 +155,7 @@ class stock_move_scrap(osv.osv_memory):
         @param context: A standard dictionary
         @return:
         """
-        if not context:
+        if context is None:
             context = {}
         move_obj = self.pool.get('stock.move')
         move_ids = context['active_ids']
@@ -181,7 +181,7 @@ class split_in_production_lot(osv.osv_memory):
         @param context: A standard dictionary
         @return: Default values of fields
         """
-        if not context:
+        if context is None:
             context = {}
 
         res = super(split_in_production_lot, self).default_get(cr, uid, fields, context=context)
@@ -215,7 +215,7 @@ class split_in_production_lot(osv.osv_memory):
         @param context: A standard dictionary
         @return:
         """
-        if not context:
+        if context is None:
             context = {}
         self.split(cr, uid, ids, context.get('active_ids'), context=context)
         return {}
@@ -233,8 +233,6 @@ class split_in_production_lot(osv.osv_memory):
         prodlot_obj = self.pool.get('stock.production.lot')
         move_obj = self.pool.get('stock.move')
         new_move = []
-        if not context:
-            context = {}
         for data in self.browse(cr, uid, ids, context=context):
             for move in move_obj.browse(cr, uid, move_ids, context=context):
                 move_qty = move.product_qty
diff --git a/addons/stock/wizard/stock_partial_move.py b/addons/stock/wizard/stock_partial_move.py
index 5df0de48ddf..edd079315f3 100644
--- a/addons/stock/wizard/stock_partial_move.py
+++ b/addons/stock/wizard/stock_partial_move.py
@@ -51,7 +51,7 @@ class stock_partial_move(osv.osv_memory):
         res = super(stock_partial_move, self).view_init(cr, uid, fields_list, context=context)
         move_obj = self.pool.get('stock.move')
     
-        if not context:
+        if context is None:
             context = {}
         for move in move_obj.browse(cr, uid, context.get('active_ids', []), context=context):
             if move.state in ('done', 'cancel'):
@@ -77,7 +77,7 @@ class stock_partial_move(osv.osv_memory):
 
     def __get_active_stock_moves(self, cr, uid, context=None):
         move_obj = self.pool.get('stock.move')
-        if not context:
+        if context is None:
             context = {}
                
         res = []
@@ -151,7 +151,7 @@ class stock_partial_move(osv.osv_memory):
         @return: A dictionary which of fields with values.
         """
     
-        if not context:
+        if context is None:
             context = {}
         move_obj = self.pool.get('stock.move')
         
diff --git a/addons/stock/wizard/stock_partial_picking.py b/addons/stock/wizard/stock_partial_picking.py
index a7d444f95b2..60e2750db08 100644
--- a/addons/stock/wizard/stock_partial_picking.py
+++ b/addons/stock/wizard/stock_partial_picking.py
@@ -33,7 +33,7 @@ class stock_partial_picking(osv.osv_memory):
     def view_init(self, cr, uid, fields_list, context=None):
         res = super(stock_partial_picking, self).view_init(cr, uid, fields_list, context=context)
         pick_obj = self.pool.get('stock.picking')
-        if not context:
+        if context is None:
             context={}
         for pick in pick_obj.browse(cr, uid, context.get('active_ids', []), context=context):
             need_product_cost = (pick.type == 'in')
@@ -157,11 +157,9 @@ class stock_partial_picking(osv.osv_memory):
         @param context: A standard dictionary
         @return: A dictionary which of fields with values.
         """
-        if not context:
-            context = {}
         res = super(stock_partial_picking, self).default_get(cr, uid, fields, context=context)
         pick_obj = self.pool.get('stock.picking')
-        if not context:
+        if context is None:
             context={}
         if 'date' in fields:
             res.update({'date': time.strftime('%Y-%m-%d %H:%M:%S')})
diff --git a/addons/stock/wizard/stock_return_picking.py b/addons/stock/wizard/stock_return_picking.py
index 14f5bab76ee..85f3d0ba9ad 100644
--- a/addons/stock/wizard/stock_return_picking.py
+++ b/addons/stock/wizard/stock_return_picking.py
@@ -39,7 +39,7 @@ class stock_return_picking(osv.osv_memory):
          @param context: A standard dictionary
          @return: A dictionary with default values for all field in ``fields``
         """
-        if not context:
+        if context is None:
             context = {}
         res = super(stock_return_picking, self).default_get(cr, uid, fields, context=context)
         record_id = context and context.get('active_id', False) or False
@@ -66,7 +66,7 @@ class stock_return_picking(osv.osv_memory):
          @param context: A standard dictionary 
          @return: New arch of view with new columns.
         """
-        if not context:
+        if context is None:
             context = {}
         res = super(stock_return_picking, self).view_init(cr, uid, fields_list, context=context)
         record_id = context and context.get('active_id', False) 
@@ -142,7 +142,7 @@ class stock_return_picking(osv.osv_memory):
          @param context: A standard dictionary 
          @return: A dictionary which of fields with values. 
         """
-        if not context:
+        if context is None:
             context = {} 
         record_id = context and context.get('active_id', False) or False
         move_obj = self.pool.get('stock.move')
diff --git a/addons/stock/wizard/stock_split_move.py b/addons/stock/wizard/stock_split_move.py
index a54b8bfba17..fb024b6f6a0 100644
--- a/addons/stock/wizard/stock_split_move.py
+++ b/addons/stock/wizard/stock_split_move.py
@@ -34,7 +34,7 @@ class stock_split_move_line(osv.osv_memory):
          @param context: A standard dictionary 
          @return: A dictionary which of fields with values. 
         """ 
-        if not context:
+        if context is None:
             context = {}
         res = super(stock_split_move_line, self).default_get(cr, uid, fields, context=context)
         record_id = context and context.get('active_id', False) or False
@@ -101,7 +101,7 @@ class stock_split_move_line(osv.osv_memory):
          @param context: A standard dictionary 
          @return: A dictionary which of fields with values. 
         """ 
-        if not context:
+        if context is None:
             context = {}
         move_obj = self.pool.get('stock.move')
         record_id = context and context.get('active_id', False) or False
diff --git a/addons/stock/wizard/stock_splitinto.py b/addons/stock/wizard/stock_splitinto.py
index e2ce82110c5..3782df00f16 100644
--- a/addons/stock/wizard/stock_splitinto.py
+++ b/addons/stock/wizard/stock_splitinto.py
@@ -34,7 +34,7 @@ class stock_split_into(osv.osv_memory):
     }
 
     def split(self, cr, uid, data, context=None):
-        if not context:
+        if context is None:
             context = {}
         rec_id = context and context.get('active_ids', False)
         move_obj = self.pool.get('stock.move')
diff --git a/addons/stock/wizard/stock_traceability.py b/addons/stock/wizard/stock_traceability.py
index 99bc2676667..44026c22679 100644
--- a/addons/stock/wizard/stock_traceability.py
+++ b/addons/stock/wizard/stock_traceability.py
@@ -38,7 +38,7 @@ class action_traceability(osv.osv_memory):
         @param context: A standard dictionary 
         @return: A dictionary of values
         """
-        if not context:
+        if context is None:
             context = {}
         type1 = context['type'] or 'move_history_ids2'
         field = context['field'] or 'tracking_id'
diff --git a/addons/stock_invoice_directly/wizard/stock_invoice.py b/addons/stock_invoice_directly/wizard/stock_invoice.py
index 59a8512c5f3..def35742b99 100644
--- a/addons/stock_invoice_directly/wizard/stock_invoice.py
+++ b/addons/stock_invoice_directly/wizard/stock_invoice.py
@@ -33,7 +33,7 @@ class invoice_directly(osv.osv_memory):
         @param context: A standard dictionary
         @return:
         """
-        if not context:
+        if context is None:
             context = {}
         result = super(invoice_directly, self).do_partial(cr, uid, ids, context)
         pick_obj = self.pool.get('stock.picking')
diff --git a/addons/stock_location/procurement_pull.py b/addons/stock_location/procurement_pull.py
index 4d47ee21dfa..7122e5ccd12 100644
--- a/addons/stock_location/procurement_pull.py
+++ b/addons/stock_location/procurement_pull.py
@@ -25,8 +25,6 @@ from tools.translate import _
 class procurement_order(osv.osv):
     _inherit = 'procurement.order'
     def check_buy(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for procurement in self.browse(cr, uid, ids, context=context):
             for line in procurement.product_id.flow_pull_ids:
                 if line.location_id==procurement.location_id:
@@ -34,8 +32,6 @@ class procurement_order(osv.osv):
         return super(procurement_order, self).check_buy(cr, uid, ids)
 
     def check_produce(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for procurement in self.browse(cr, uid, ids, context=context):
             for line in procurement.product_id.flow_pull_ids:
                 if line.location_id==procurement.location_id:
@@ -43,8 +39,6 @@ class procurement_order(osv.osv):
         return super(procurement_order, self).check_produce(cr, uid, ids)
 
     def check_move(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for procurement in self.browse(cr, uid, ids, context=context):
             for line in procurement.product_id.flow_pull_ids:
                 if line.location_id==procurement.location_id:
@@ -56,8 +50,6 @@ class procurement_order(osv.osv):
         move_obj = self.pool.get('stock.move')
         picking_obj=self.pool.get('stock.picking')
         wf_service = netsvc.LocalService("workflow")
-        if not context:
-            context = {}
         for proc in proc_obj.browse(cr, uid, ids, context=context):
             line = None
             for line in proc.product_id.flow_pull_ids:
diff --git a/addons/stock_location/stock_location.py b/addons/stock_location/stock_location.py
index b937920fd70..26507e74e7e 100644
--- a/addons/stock_location/stock_location.py
+++ b/addons/stock_location/stock_location.py
@@ -107,8 +107,6 @@ class stock_move(osv.osv):
         'cancel_cascade': fields.boolean('Cancel Cascade', help='If checked, when this move is cancelled, cancel the linked move too')
     }
     def action_cancel(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for m in self.browse(cr, uid, ids, context=context):
             if m.cancel_cascade and m.move_dest_id:
                 self.action_cancel(cr, uid, [m.move_dest_id.id], context=context)
@@ -119,8 +117,6 @@ stock_move()
 class stock_location(osv.osv):
     _inherit = 'stock.location'
     def chained_location_get(self, cr, uid, location, partner=None, product=None, context=None):
-        if not context:
-            context = {}
         if product:
             for path in product.path_ids:
                 if path.location_from_id.id == location.id:
diff --git a/addons/stock_planning/stock_planning.py b/addons/stock_planning/stock_planning.py
index 227add4cfb9..d9a6eb6e84c 100644
--- a/addons/stock_planning/stock_planning.py
+++ b/addons/stock_planning/stock_planning.py
@@ -48,14 +48,10 @@ class stock_period(osv.osv):
     }
     
     def button_open(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state': 'open'})
         return True
     
     def button_close(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state': 'close'})
         return True
 
@@ -196,8 +192,6 @@ class stock_sale_forecast(osv.osv):
     def _to_default_uom_factor(self, cr, uid, product_id, uom_id, context=None):
         uom_obj = self.pool.get('product.uom')
         product_obj = self.pool.get('product.product')
-        if not context:
-            context = {}
         product = product_obj.browse(cr, uid, product_id, context=context)
         uom = uom_obj.browse(cr, uid, uom_id, context=context)
         coef = uom.factor
@@ -208,8 +202,6 @@ class stock_sale_forecast(osv.osv):
     def _from_default_uom_factor(self, cr, uid, product_id, uom_id, context=None):
         uom_obj = self.pool.get('product.uom')
         product_obj = self.pool.get('product.product')
-        if not context:
-            context = {}
         product = product_obj.browse(cr, uid, product_id, context=context)
         uom = uom_obj.browse(cr, uid, uom_id, context=context)
         res = uom.factor
@@ -310,7 +302,7 @@ class stock_planning(osv.osv):
     _name = "stock.planning"
 
     def _get_in_out(self, cr, uid, val, date_start, date_stop, direction, done, context=None):
-        if not context:
+        if context is None:
             context = {}
         product_obj = self.pool.get('product.product')
         mapping = {'in': {
@@ -356,8 +348,6 @@ class stock_planning(osv.osv):
 
     def _to_planning_uom(self, cr, uid, val, qtys, context=None):
         res_qty = 0
-        if not context:
-            context = {}
         if qtys:
             uom_obj = self.pool.get('product.uom')
             for qty, prod_uom in qtys:
@@ -370,8 +360,6 @@ class stock_planning(osv.osv):
 
     def _get_forecast(self, cr, uid, ids, field_names, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         for val in self.browse(cr, uid, ids, context=context):
             res[val.id] = {}
             valid_part = val.confirmed_forecasts_only and " AND state = 'validated'" or ""
@@ -394,7 +382,7 @@ class stock_planning(osv.osv):
         return res
 
     def _get_stock_start(self, cr, uid, val, date, context=None):
-        if not context:
+        if context is None:
             context = {}
         context['from_date'] = None
         context['to_date'] = date
@@ -409,8 +397,6 @@ class stock_planning(osv.osv):
 
     def _get_past_future(self, cr, uid, ids, field_names, arg, context=None):
         res = {}
-        if not context:
-            context = {}
         for val in self.browse(cr, uid, ids, context=context):
             if val.period_id.date_stop < time.strftime('%Y-%m-%d'):
                 res[val.id] = 'Past'
@@ -420,8 +406,6 @@ class stock_planning(osv.osv):
 
     def _get_op(self, cr, uid, ids, field_names, arg, context=None):  # op = OrderPoint
         res = {}
-        if not context:
-            context = {}
         for val in self.browse(cr, uid, ids, context=context):
             res[val.id]={}
             cr.execute("SELECT product_min_qty, product_max_qty, product_uom  \
@@ -537,8 +521,6 @@ class stock_planning(osv.osv):
     def _to_default_uom_factor(self, cr, uid, product_id, uom_id, context=None):
         uom_obj = self.pool.get('product.uom')
         product_obj = self.pool.get('product.product')
-        if not context:
-            context = {}
         product = product_obj.browse(cr, uid, product_id, context=context)
         uom = uom_obj.browse(cr, uid, uom_id, context=context)
         coef = uom.factor
@@ -615,8 +597,6 @@ class stock_planning(osv.osv):
     def _qty_to_standard(self, cr, uid, val, context=None):
         uos = False
         uos_qty = 0.0
-        if not context:
-            context = {}
         if val.product_uom.category_id.id == val.product_id.uom_id.category_id.id:
             uom_qty = val.incoming_left
             uom = val.product_uom.id
diff --git a/addons/stock_planning/wizard/stock_planning_create_periods.py b/addons/stock_planning/wizard/stock_planning_create_periods.py
index e24382b2405..13a822ed3fe 100644
--- a/addons/stock_planning/wizard/stock_planning_create_periods.py
+++ b/addons/stock_planning/wizard/stock_planning_create_periods.py
@@ -31,8 +31,6 @@ class stock_period_createlines(osv.osv_memory):
     _name = "stock.period.createlines"
 
     def _get_new_period_start(self, cr, uid, context=None):
-        if not context:
-            context = {}
         cr.execute("select max(date_stop) from stock_period")
         result = cr.fetchone()
         last_date = result and result[0] or False
@@ -55,7 +53,7 @@ class stock_period_createlines(osv.osv_memory):
     }
     
     def create_stock_periods(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         interval = context.get('interval',0)
         name = context.get('name','Daily')
diff --git a/addons/stock_planning/wizard/stock_planning_forecast.py b/addons/stock_planning/wizard/stock_planning_forecast.py
index c88794d4d42..d38173a665d 100644
--- a/addons/stock_planning/wizard/stock_planning_forecast.py
+++ b/addons/stock_planning/wizard/stock_planning_forecast.py
@@ -50,8 +50,6 @@ class stock_sale_forecast_createlines(osv.osv_memory):
         prod_categ_obj = self.pool.get('product.category')
         template_obj = self.pool.get('product.template')
         forecast_lines = []
-        if not context:
-            context = {}
         for f in self.browse(cr, uid, ids, context=context):
             categ_ids =  f.product_categ_id.id and [f.product_categ_id.id] or []
             prod_categ_ids = prod_categ_obj.search(cr, uid, [('parent_id','child_of', categ_ids)])
diff --git a/addons/subscription/subscription.py b/addons/subscription/subscription.py
index 6852cdbfe89..c015f599e7d 100644
--- a/addons/subscription/subscription.py
+++ b/addons/subscription/subscription.py
@@ -40,8 +40,6 @@ class subscription_document(osv.osv):
     }
     
     def write(self, cr, uid, ids, vals, context=None):
-        if not context:
-            context = {}
         if 'model' in vals:
             raise osv.except_osv(_('Error !'),_('You cannot modify the Object linked to the Document Type!\nCreate another Document instead !'))
         return super(subscription_document, self).write(cr, uid, ids, vals, context=context)
@@ -94,8 +92,6 @@ class subscription_subscription(osv.osv):
     }
 
     def set_process(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for row in self.read(cr, uid, ids):
             mapping = {'name':'name','interval_number':'interval_number','interval_type':'interval_type','exec_init':'numbercall','date_init':'nextcall'}
             res = {'model':'subscription.subscription', 'args': repr([[row['id']]]), 'function':'model_copy', 'priority':6, 'user_id':row['user_id'] and row['user_id'][0]}
@@ -106,8 +102,6 @@ class subscription_subscription(osv.osv):
         return True
 
     def model_copy(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         for row in self.read(cr, uid, ids):
             if not row.get('cron_id',False):
                 continue
@@ -143,8 +137,6 @@ class subscription_subscription(osv.osv):
         return True
 
     def set_done(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         res = self.read(cr,uid, ids, ['cron_id'])
         ids2 = [x['cron_id'][0] for x in res if x['id']]
         self.pool.get('ir.cron').write(cr, uid, ids2, {'active':False})
@@ -152,8 +144,6 @@ class subscription_subscription(osv.osv):
         return True
 
     def set_draft(self, cr, uid, ids, context=None):
-        if not context:
-            context = {}
         self.write(cr, uid, ids, {'state':'draft'})
         return True
 subscription_subscription()
diff --git a/addons/survey/survey.py b/addons/survey/survey.py
index 08466d39a06..85477b3c221 100644
--- a/addons/survey/survey.py
+++ b/addons/survey/survey.py
@@ -47,8 +47,6 @@ class survey(osv.osv):
     _rec_name = 'title'
 
     def default_get(self, cr, uid, fields, context=None):
-        if not context:
-            context = {}
         data = super(survey, self).default_get(cr, uid, fields, context)
         return data
 
@@ -97,8 +95,6 @@ class survey(osv.osv):
         return True
 
     def copy(self, cr, uid, id, default=None,context=None):
-        if not context:
-            context = {}
         raise osv.except_osv(_('Warning !'),_('You cannot duplicate the resource!'))
 
     def action_print_survey(self, cr, uid, ids, context=None):
@@ -111,7 +107,7 @@ class survey(osv.osv):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for print survey form.
         """
-        if not context:
+        if context is None:
             context = {}
         datas = {}
         if 'response_id' in context:
@@ -178,7 +174,7 @@ class survey_page(osv.osv):
     }
 
     def default_get(self, cr, uid, fields, context=None):
-        if not context:
+        if context is None:
             context = {}
         data = super(survey_page, self).default_get(cr, uid, fields, context)
         if context.get('line_order',False):
@@ -189,7 +185,7 @@ class survey_page(osv.osv):
         return data
 
     def survey_save(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         search_obj = self.pool.get('ir.ui.view')
         search_id = search_obj.search(cr,uid,[('model','=','survey.question.wiz'),('name','=','Survey Search')])
@@ -206,8 +202,6 @@ class survey_page(osv.osv):
         }
 
     def copy(self, cr, uid, id, default=None, context=None):
-        if not context:
-            context = {}
         raise osv.except_osv(_('Warning !'),_('You cannot duplicate the resource!'))
 
 survey_page()
@@ -222,8 +216,6 @@ class survey_question(osv.osv):
         if len(ids) == 0:
             return {}
         val = {}
-        if not context:
-            context = {}
         cr.execute("select question_id, count(id) as Total_response from \
                 survey_response_line where state='done' and question_id IN %s\
                  group by question_id" ,(tuple(ids),))
@@ -454,8 +446,6 @@ class survey_question(osv.osv):
     def create(self, cr, uid, vals, context=None):
         minimum_ans = 0
         maximum_ans = 0
-        if not context:
-            context = {}
         if vals.has_key('answer_choice_ids') and  not len(vals['answer_choice_ids']):
             if vals.has_key('type') and vals['type'] not in ['descriptive_text', 'single_textbox', 'comment','table']:
                 raise osv.except_osv(_('Warning !'),_("You must enter one or more answer."))
@@ -490,7 +480,7 @@ class survey_question(osv.osv):
         return res
 
     def survey_save(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         search_obj = self.pool.get('ir.ui.view')
         search_id = search_obj.search(cr,uid,[('model','=','survey.question.wiz'),('name','=','Survey Search')])
@@ -507,7 +497,7 @@ class survey_question(osv.osv):
         }
 
     def default_get(self, cr, uid, fields, context=None):
-        if not context:
+        if context is None:
             context = {}
         data = super(survey_question, self).default_get(cr, uid, fields, context)
         if context.get('line_order',False):
@@ -527,13 +517,13 @@ class survey_question_column_heading(osv.osv):
     _rec_name = 'title'
 
     def _get_in_visible_rating_weight(self,cr, uid, context=None):
-        if not context:
+        if context is None:
             context = {}
         if context.get('in_visible_rating_weight', False):
             return context['in_visible_rating_weight']
         return False
     def _get_in_visible_menu_choice(self,cr, uid, context=None):
-        if not context:
+        if context is None:
             context = {}
         if context.get('in_visible_menu_choice', False):
             return context['in_visible_menu_choice']
@@ -561,8 +551,6 @@ class survey_answer(osv.osv):
 
     def _calc_response_avg(self, cr, uid, ids, field_name, arg, context=None):
         val = {}
-        if not context:
-            context = {}
         for rec in self.browse(cr, uid, ids, context=context):
             cr.execute("select count(question_id) ,(select count(answer_id) \
                 from survey_response_answer sra, survey_response_line sa \
@@ -582,7 +570,7 @@ class survey_answer(osv.osv):
         return val
 
     def _get_in_visible_answer_type(self,cr, uid, context=None):
-        if not context:
+        if context is None:
             context = {}
         return context.get('in_visible_answer_type', False)
 
@@ -605,7 +593,7 @@ class survey_answer(osv.osv):
     }
 
     def default_get(self, cr, uid, fields, context=None):
-        if not context:
+        if context is None:
             context = {}
         data = super(survey_answer, self).default_get(cr, uid, fields, context)
         if context.get('line_order', False):
@@ -644,8 +632,6 @@ class survey_response(osv.osv):
         return res
 
     def copy(self, cr, uid, id, default=None,context=None):
-        if not context:
-            context = {}
         raise osv.except_osv(_('Warning !'),_('You cannot duplicate the resource!'))
 
 survey_response()
@@ -744,8 +730,6 @@ class survey_request(osv.osv):
         return True
 
     def on_change_user(self, cr, uid, ids, user_id, context=None):
-        if not context:
-            context = {}
         if user_id:
             user_obj = self.pool.get('res.users')
             user = user_obj.browse(cr, uid, user_id, context=context)
diff --git a/addons/survey/wizard/survey_answer.py b/addons/survey/wizard/survey_answer.py
index f1bccdd0225..90d702f13ed 100644
--- a/addons/survey/wizard/survey_answer.py
+++ b/addons/survey/wizard/survey_answer.py
@@ -479,7 +479,7 @@ class survey_question_wiz(osv.osv_memory):
         @return : Dictionary value for fields list with value.
         """
         value = {}
-        if not context:
+        if context is None:
             context = {}
         for field in fields_list:
             if field.split('_')[0] == 'progress':
@@ -560,6 +560,7 @@ class survey_question_wiz(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : True.
         """
+        if context is None: context = {}
         if context.has_key('active') and context.get('active',False):
             return True
 
@@ -1019,7 +1020,7 @@ class survey_question_wiz(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for Open new survey.Qestion form.
         """
-        if not context:
+        if context is None:
             context = {}
         for key,val in context.items():
             if type(key) == type(True):
@@ -1047,7 +1048,7 @@ class survey_question_wiz(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for Open new survey.page form.
         """
-        if not context:
+        if context is None:
             context = {}
         for key,val in context.items():
             if type(key) == type(True):
@@ -1075,7 +1076,7 @@ class survey_question_wiz(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for Open Edit survey.page form.
         """
-        if not context:
+        if context is None:
             context = {}
         for key,val in context.items():
             if type(key) == type(True):
@@ -1104,7 +1105,7 @@ class survey_question_wiz(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for Open next survey.page form, but delete the selected page.
         """
-        if not context:
+        if context is None:
             context = {}
         for key,val in context.items():
             if type(key) == type(True):
@@ -1137,7 +1138,7 @@ class survey_question_wiz(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for Open Edit survey.question form.
         """
-        if not context:
+        if context is None:
             context = {}
         for key,val in context.items():
             if type(key) == type(True):
@@ -1166,7 +1167,7 @@ class survey_question_wiz(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for Open same survey.page form, but delete the selected survey.question in current survey.page.
         """
-        if not context:
+        if context is None:
             context = {}
         for key,val in context.items():
             if type(key) == type(True):
@@ -1200,7 +1201,7 @@ class survey_question_wiz(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for Open Previous Answer form.
         """
-        if not context:
+        if context is None:
             context = {}
         search_obj = self.pool.get('ir.ui.view')
         surv_name_wiz = self.pool.get('survey.name.wiz')
@@ -1232,7 +1233,7 @@ class survey_question_wiz(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for Open Next Answer form.
         """
-        if not context:
+        if context is None:
             context = {}
         search_obj = self.pool.get('ir.ui.view')
         surv_name_wiz = self.pool.get('survey.name.wiz')
@@ -1264,7 +1265,7 @@ class survey_question_wiz(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for Open Next survey.page form.
         """
-        if not context:
+        if context is None:
             context = {}
         surv_name_wiz = self.pool.get('survey.name.wiz')
         search_obj = self.pool.get('ir.ui.view')
@@ -1291,7 +1292,7 @@ class survey_question_wiz(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for Open Previous survey.page form.
         """
-        if not context:
+        if context is None:
             context = {}
         surv_name_wiz = self.pool.get('survey.name.wiz')
         search_obj = self.pool.get('ir.ui.view')
diff --git a/addons/survey/wizard/survey_browse_answer.py b/addons/survey/wizard/survey_browse_answer.py
index c8979ee3a6f..81afc061429 100644
--- a/addons/survey/wizard/survey_browse_answer.py
+++ b/addons/survey/wizard/survey_browse_answer.py
@@ -61,6 +61,7 @@ class survey_browse_answer(osv.osv_memory):
         @param context: A standard dictionary for contextual values,
         @return : Dictionary value for Open the browse answer wizard.
         """
+        if context is None: context = {}
         record = self.read(cr, uid, ids, [])
         record = record and record[0] or {} 
         if record['response_id']:
diff --git a/addons/survey/wizard/survey_print.py b/addons/survey/wizard/survey_print.py
index 325c1ac3598..095caeccc5a 100644
--- a/addons/survey/wizard/survey_print.py
+++ b/addons/survey/wizard/survey_print.py
@@ -56,8 +56,6 @@ class survey_print(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for print survey form.
         """
-        if not context:
-            context = {}
 
         datas = {'ids' : self.read(cr, uid, ids, [], context)[0]['survey_ids']}
         res = self.read(cr, uid, ids, ['survey_title', 'orientation', 'paper_size',\
diff --git a/addons/survey/wizard/survey_print_answer.py b/addons/survey/wizard/survey_print_answer.py
index 8e3ae95bdca..68ebd399871 100644
--- a/addons/survey/wizard/survey_print_answer.py
+++ b/addons/survey/wizard/survey_print_answer.py
@@ -56,7 +56,7 @@ class survey_print_answer(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return : Dictionary value for created survey answer report
         """
-        if not context:
+        if context is None:
             context = {}
         datas = {'ids': context.get('active_ids', [])}
         res = self.read(cr, uid, ids, ['response_ids', 'orientation', 'paper_size',\
diff --git a/addons/survey/wizard/survey_print_statistics.py b/addons/survey/wizard/survey_print_statistics.py
index 4ffe13dd25d..6899b1dbf25 100644
--- a/addons/survey/wizard/survey_print_statistics.py
+++ b/addons/survey/wizard/survey_print_statistics.py
@@ -42,7 +42,7 @@ class survey_print_statistics(osv.osv_memory):
         @param context: A standard dictionary for contextual values
         @return: Dictionary value for created survey statistics report
         """
-        if not context:
+        if context is None:
             context = {}
         datas = {'ids': context.get('active_ids', [])}
         res = self.read(cr, uid, ids, ['survey_ids'], context)
diff --git a/addons/survey/wizard/survey_selection.py b/addons/survey/wizard/survey_selection.py
index 2ef83d38fcf..123867fed80 100644
--- a/addons/survey/wizard/survey_selection.py
+++ b/addons/survey/wizard/survey_selection.py
@@ -121,6 +121,7 @@ class survey_name_wiz(osv.osv_memory):
         """
         survey_obj = self.pool.get('survey')
         search_obj = self.pool.get('ir.ui.view')
+        if context is None: context = {}
 
         sur_id = self.read(cr, uid, ids, [])[0]
         survey_id = sur_id['survey_id']
diff --git a/addons/survey/wizard/survey_send_invitation.py b/addons/survey/wizard/survey_send_invitation.py
index 9702b4d2de9..361f7388f6f 100644
--- a/addons/survey/wizard/survey_send_invitation.py
+++ b/addons/survey/wizard/survey_send_invitation.py
@@ -60,7 +60,7 @@ class survey_send_invitation(osv.osv_memory):
         return ''.join([choice(chars) for i in range(6)])
 
     def default_get(self, cr, uid, fields_list, context=None):
-        if not context:
+        if context is None:
             context = {}
         data = super(survey_send_invitation, self).default_get(cr, uid, fields_list, context)
         survey_obj = self.pool.get('survey')
@@ -94,7 +94,7 @@ class survey_send_invitation(osv.osv_memory):
 
 
     def action_send(self, cr, uid, ids, context=None):
-        if not context:
+        if context is None:
             context = {}
         record = self.read(cr, uid, ids, [])
         survey_ids =  context.get('active_ids', [])
@@ -224,7 +224,7 @@ class survey_send_invitation_log(osv.osv_memory):
     }
 
     def default_get(self, cr, uid, fields_list, context=None):
-        if not context:
+        if context is None:
             context = {}
         data = super(survey_send_invitation_log, self).default_get(cr, uid, fields_list, context)
         data['note'] = context.get('note', '')
diff --git a/addons/thunderbird/installer.py b/addons/thunderbird/installer.py
index 08298e9e52f..e145501fee2 100644
--- a/addons/thunderbird/installer.py
+++ b/addons/thunderbird/installer.py
@@ -32,8 +32,6 @@ class thunderbird_installer(osv.osv_memory):
     _inherit = 'res.config.installer'
 
     def default_get(self, cr, uid, fields, context=None):
-        if not context:
-            context = {}
         data = super(thunderbird_installer, self).default_get(cr, uid, fields, context)
         data['pdf_file'] = 'http://doc.openerp.com/book/2/2_6_Comms/2_6_Comms_thunderbird.html'
         file = open(addons.get_module_resource('thunderbird','plugin', 'openerp_plugin.xpi'),'rb')
diff --git a/addons/wiki/wiki.py b/addons/wiki/wiki.py
index f6a2f71fd4c..f3503936c78 100644
--- a/addons/wiki/wiki.py
+++ b/addons/wiki/wiki.py
@@ -62,8 +62,6 @@ class wiki_group(osv.osv):
         @param ids: List of open wiki group’s IDs
         @return: dictionay of open wiki window on give group id
         """
-        if not context:
-            context = {}
         if type(ids) in (int,long,):
             ids = [ids]
         group_id = False
@@ -140,8 +138,6 @@ class wiki_wiki2(osv.osv):
 
         if (not group_id) or content:
             return {}
-        if not context:
-            context = {}
         grp = self.pool.get('wiki.groups').browse(cr, uid, group_id, context=context)
         section = '0'
         for page in grp.page_ids:
@@ -166,8 +162,6 @@ class wiki_wiki2(osv.osv):
             @param uid: the current user’s ID for security checks,
             @param id: Give wiki page's ID """
 
-        if not context:
-            context = {}
         return super(wiki_wiki2, self).copy_data(cr, uid, id, {'wiki_id': False}, context)
 
     def create_history(self, cr, uid, ids, vals, context=None):
diff --git a/addons/wiki/wizard/wiki_create_menu.py b/addons/wiki/wizard/wiki_create_menu.py
index fdb952bb52e..f95c1e2dffd 100644
--- a/addons/wiki/wizard/wiki_create_menu.py
+++ b/addons/wiki/wizard/wiki_create_menu.py
@@ -39,7 +39,7 @@ class wiki_create_menu(osv.osv_memory):
         @param ids: List of create menu’s IDs
 
         """
-        if not context:
+        if context is None:
             context = {}
         obj_wiki_group = self.pool.get('wiki.groups')
         obj_view = self.pool.get('ir.ui.view')
diff --git a/addons/wiki/wizard/wiki_make_index.py b/addons/wiki/wizard/wiki_make_index.py
index 83324166dbd..6b159b7ac30 100644
--- a/addons/wiki/wizard/wiki_make_index.py
+++ b/addons/wiki/wizard/wiki_make_index.py
@@ -35,7 +35,7 @@ class wiki_make_index(osv.osv_memory):
         @param ids: list of wiki index’s IDs
 
         """
-        if not context:
+        if context is None:
             context = {}
         data = context and context.get('active_ids', []) or []
 
diff --git a/addons/wiki/wizard/wiki_show_diff.py b/addons/wiki/wizard/wiki_show_diff.py
index f807a5c733c..278c91064df 100644
--- a/addons/wiki/wizard/wiki_show_diff.py
+++ b/addons/wiki/wizard/wiki_show_diff.py
@@ -33,7 +33,7 @@ class showdiff(osv.osv_memory):
         """ @param cr: the current row, from the database cursor,
         @param uid: the current user’s ID for security checks,
         """
-        if not context:
+        if context is None:
             context = {}
         history = self.pool.get('wiki.wiki.history')
         ids = context.get('active_ids', [])
diff --git a/addons/wiki/wizard/wiki_wiki_page_open.py b/addons/wiki/wizard/wiki_wiki_page_open.py
index ce71a116bd9..1fe4f8acc49 100644
--- a/addons/wiki/wizard/wiki_wiki_page_open.py
+++ b/addons/wiki/wizard/wiki_wiki_page_open.py
@@ -35,7 +35,7 @@ class wiki_wiki_page_open(osv.osv_memory):
         @param ids: List of open wiki page’s IDs
         @return: dictionay of open wiki window on give group id
         """
-        if not context:
+        if context is None:
             context = {}
         group_ids = context.get('active_ids', [])
         for group in self.pool.get('wiki.groups').browse(cr, uid, group_ids, context=context):