human
Solve the following python programming problem given the following code:
@ mock.patch.object (notifications, 'send_update') 
@ mock.patch.object (cells_rpcapi.CellsAPI, 'instance_update_from_api') 
@ mock.patch.object (cells_rpcapi.CellsAPI, 'instance_update_at_top') 
@ mock.patch.object (db, 'instance_update_and_get_original') 
def _test_skip_cells_sync_helper(self, mock_db_update, mock_update_at_top, mock_update_from_api, mock_notif_update, cell_type) : 
    self.flags (enable = True, cell_type = cell_type, group = 'cells') 
    inst = fake_instance.fake_instance_obj (self.context, cell_name = 'fake') 
    inst.vm_state = 'foo' 
    inst.task_state = 'bar' 
    inst.cell_name = 'foo!bar@baz' 
    old_ref = dict (base.obj_to_primitive (inst), vm_state = 'old', task_state = 'old') 
    new_ref = dict (old_ref, vm_state = 'foo', task_state = 'bar') 
    newer_ref = dict (new_ref, vm_state = 'bar', task_state = 'foo') 
    mock_db_update.side_effect = [(old_ref, new_ref), (new_ref, old_ref)] 
    with inst.skip_cells_sync () : 
        inst.save () 
mock_update_at_top.assert_has_calls ([]) 
    mock_update_from_api.assert_has_calls ([]) 
    self.assertFalse (mock_notif_update.called) 
    inst.vm_state = 'bar' 
    inst.task_state = 'foo' 
    def fake_update_from_api(context, instance, expected_vm_state, expected_task_state, admin_state_reset) : 
        self.assertEqual ('foo!bar@baz', instance.cell_name) 
with mock.patch.object (cells_rpcapi.CellsAPI, 'instance_update_from_api', side_effect = fake_update_from_api) as fake_update_from_api : 
        inst.save () 
self.assertEqual ('foo!bar@baz', inst.cell_name) 
    self.assertTrue (mock_notif_update.called) 
    if (cell_type == 'compute') : 
        mock_update_at_top.assert_called_once_with (self.context, mock.ANY) 
        expected_inst_p = base.obj_to_primitive (inst) 
        actual_inst = mock_update_at_top.call_args [0] [1] 
        actual_inst_p = base.obj_to_primitive (actual_inst) 
        self.assertEqual (expected_inst_p, actual_inst_p) 
        self.assertFalse (fake_update_from_api.called) 
else : 
        if...

    
    

    Fix the buggy line: mock_db_update.side_effect = [(old_ref, new_ref), (new_ref, old_ref)]
assistant
#Here is Python code to fix the buggy line: mock_db_update.

mock_db_update.side_effect = [(old_ref, new_ref), (new_ref, newer_ref)]