def METHOD_NAME(base, left_additional, right_additional):
    left = deepcopy(base) + left_additional
    right = deepcopy(base) + right_additional
    expected = list(set(deepcopy(base) + left_additional + right_additional))
    got = merge_lists(base, left, right)
    assert len(got) == len(expected)
    assert all([expected_item in expected + got for expected_item in expected])