fixup! fixup! [ADD] easy_my_coop: effective date field on operation request

easy_my_coop/models/operation_request.py

@@ -93,7 +93,9 @@ class operation_request(models.Model):
     def _constrain_effective_date(self):
         for obj in self:
             if obj.effective_date > fields.Datetime.now():
-                raise ValidationError("The effective date can not be in the future.")\
+                raise ValidationError(
+                    _("The effective date can not be in the future.")
+                )
 
     @api.multi
     def approve_operation(self):