Update mass_object.py

mass_editing/models/mass_object.py

@@ -39,8 +39,8 @@ class MassObject(models.Model):
             model_list = [self.model_id.id]
             active_model_obj = self.env[self.model_id.model]
             if active_model_obj._inherits:
-                keys = active_model_obj._inherits.keys()
-                inherits_model_list = model_obj.search([('model', 'in', keys)])
+                model_names = active_model_obj._inherits.keys()
+                inherits_model_list = model_obj.search([('model', 'in', list(model_names))])
                 model_list.extend((inherits_model_list and
                                    inherits_model_list.ids or []))
         self.model_list = model_list