python合并嵌套列表为一维列表

def flat_list(array):
    # 以下表达式参考自stackoverflow上的大佬
    func = lambda x: [y for l in x for y in func(l)] if isinstance(x, list) else [x]
    return func(array)


if __name__ == '__main__':
    assert flat_list([1, 2, 3]) == [1, 2, 3], "First"
    assert flat_list([1, [2, 2, 2], 4]) == [1, 2, 2, 2, 4], "Second"
    assert flat_list([[[2]], [4, [5, 6, [6], 6, 6, 6], 7]]) == [2, 4, 5, 6, 6, 6, 6, 6, 7], "Third"
    assert flat_list([-1, [1, [-2], 1], -1]) == [-1, 1, -2, 1, -1], "Four"
    print('Done! Check it')

"""题目来自checkio"""