I always figured it was because "sort" is a verb. Over time I've come to feel that functions named with a verb phrase ought to be procedure-like, in that they h

I always figured it was because "sort" is a verb. Over time I've come to feel that functions named with a verb phrase ought to be procedure-like, in that they have side effects and return either nothing (which in python means None) or some kind of error indicator (and in python you'd generally use exceptions instead). There are exceptions (e.g., the "get" prefix, used for getters, which tend to return values and have no side-effects), and, as with any rule of thumb, better to break it than create something ugly. But as rules go, I've found this one a pretty useful one to stick to.