Because this is something that could certainly have screwed you up if you didn't realize it did it, and you need to have that discipline to make sure it's doing the right thing.

因为这是一件如果你没意识到,要这么做的话,可能会令你抓狂的一件事，你需要一个规范,来确定Python做了正确的事情。

麻省理工公开课 - 计算机科学及编程导论课程节选