diff --git a/addons/account_payment/account_move_line.py b/addons/account_payment/account_move_line.py
index 35c30c686e8..9cc300d2e4b 100644
--- a/addons/account_payment/account_move_line.py
+++ b/addons/account_payment/account_move_line.py
@@ -104,7 +104,7 @@ class account_move_line(osv.osv):
                         if bank.state in bank_type:
                             line2bank[line.id] = bank.id
                             break
-                if line.id not in line2bank and line.partner_id.bank_ids:
+                if not line2bank.get(line.id) and line.partner_id.bank_ids:
                     line2bank[line.id] = line.partner_id.bank_ids[0].id
             else:
                 raise osv.except_osv(_('Error!'), _('There is no partner defined on the entry line.'))