In [1]: [4, None, 'foo'] + [7, 8, (2,3)]
Out[1]: [4, None, 'foo', 7, 8, (2, 3)]

In [2]: x = [4, None, 'foo']

In [3]: x.extend([7, 8, (2, 3)])

In [4]: x
Out[4]: [4, None, 'foo', 7, 8, (2, 3)]

使用extend实现速度更快。