[habitue]

sorted returns a new object, not mutates the original object, so it follows the convention GP is talking about. sort() also follows that rule, since it mutates, it returns None.

In terms of refutation, some things are just conventions, and breaking them has to be done with the understanding that the benefits outweigh the costs. If python were a clean slate, totally new language, you might have a discussion about the merits of mutating chaining, but as it is, the convention is not to do that, and the benefits don't buy enough to violate everyone's expectations.

[keenerd]

Counterpoint, object.next() was removed from python3 and replaced with next(object). It both modifies state and returns data. I really prefered next() as a method since it does change the state of a generator.