diff --git a/openerp/addons/base/ir/ir_model.py b/openerp/addons/base/ir/ir_model.py
index 4e21f83992e..e0158609e1c 100644
--- a/openerp/addons/base/ir/ir_model.py
+++ b/openerp/addons/base/ir/ir_model.py
@@ -257,7 +257,7 @@ class ir_model_fields(osv.osv):
         'selection': "",
         'domain': "[]",
         'name': 'x_',
-        'state': lambda self,cr,uid,ctx={}: (ctx and ctx.get('manual',False)) and 'manual' or 'base',
+        'state': lambda self,cr,uid,ctx=None: (ctx and ctx.get('manual',False)) and 'manual' or 'base',
         'on_delete': 'set null',
         'select_level': '0',
         'size': 64,
diff --git a/openerp/addons/base/ir/ir_needaction.py b/openerp/addons/base/ir/ir_needaction.py
index 39432ca6792..12f0fccee8a 100644
--- a/openerp/addons/base/ir/ir_needaction.py
+++ b/openerp/addons/base/ir/ir_needaction.py
@@ -56,7 +56,7 @@ class ir_needaction_mixin(osv.AbstractModel):
     # "Need action" API
     #------------------------------------------------------
 
-    def _needaction_count(self, cr, uid, domain=[], context=None):
+    def _needaction_count(self, cr, uid, domain=None, context=None):
         """ Get the number of actions uid has to perform. """
         dom = self._needaction_domain_get(cr, uid, context=context)
         if not dom: