diff --git a/addons/base_vat/base_vat.py b/addons/base_vat/base_vat.py
index a6b396fd506..3923b287e06 100644
--- a/addons/base_vat/base_vat.py
+++ b/addons/base_vat/base_vat.py
@@ -75,7 +75,7 @@ class res_partner(osv.osv):
         'vat_subjected': fields.boolean('VAT Legal Statement', help="Check this box if the partner is subjected to the VAT. It will be used for the VAT legal statement.")
     }
 
-    def _construct_constraint_msg(self, cr, uid, ids):
+    def _construct_constraint_msg(self, cr, uid, ids, context=None):
         def default_vat_check(cn, vn):
             # by default, a VAT number is valid if:
             #  it starts with 2 letters