进行切片的一个非常有用的特性是，在开始之前或结束之后进行较多切片不会抛出异常，只是相应地以默认方式开始或结束该序列。

One very useful feature of slicing is that slicing too much, going before the start or past the end, doesn't throw an exception but simply defaults to the start or end of the sequence, as appropriate.

youdao