def METHOD_NAME(self):
    utils.parallel_map.MAX_WORKERS = 1
    starmap = itertools.starmap
    with mock.patch("itertools.starmap") as sm:
        sm.side_effect = starmap
        self.assertEqual([1, 2, 3],
                         utils.parallel_map(lambda x: x,
                                            [[1], [2], [3]]))
        sm.assert_called()