diff --git a/addons/l10n_fr_pos_cert/models/account_bank_statement.py b/addons/l10n_fr_pos_cert/models/account_bank_statement.py
index 28afbf0d549..f0753885bc1 100644
--- a/addons/l10n_fr_pos_cert/models/account_bank_statement.py
+++ b/addons/l10n_fr_pos_cert/models/account_bank_statement.py
@@ -6,6 +6,7 @@ from openerp.exceptions import UserError
 class AccountBankStatement(models.Model):
     _inherit = 'account.bank.statement'
 
+    @api.multi
     def unlink(self):
         for statement in self.filtered(lambda s: s.company_id._is_accounting_unalterable() and s.journal_id.journal_user):
             raise UserError(_('You cannot modify anything on a bank statement (name: %s) that was created by point of sale operations.') % (statement.name,))
@@ -15,6 +16,7 @@ class AccountBankStatement(models.Model):
 class AccountBankStatementLine(models.Model):
     _inherit = 'account.bank.statement.line'
 
+    @api.multi
     def unlink(self):
         for line in self.filtered(lambda s: s.company_id._is_accounting_unalterable() and s.journal_id.journal_user):
             raise UserError(_('You cannot modify anything on a bank statement line (name: %s) that was created by point of sale operations.') % (line.name,))