> The usual preference comes down to whether you want to be explicit about implementing it or not, and whether you want to pull in default behaviour. Thanks :)

> The usual preference comes down to whether you want to be explicit about implementing it or not, and whether you want to pull in default behaviour. Thanks :) I definitely prefer things to be explicit; regardless of it being a "Zen of Python" mantra. That said, I do see the value of `Protocol` for non-annotated/legacy code, in that it gives you a convenient mechanism for this. I would be worried about it becoming a crutch, if overused, but definitely better than no annotations at all! (I don't understand your point regarding an ABC's default implementation. Isn't the point of ABCs that they're not base classes, but interfaces that define the methods required without any implementation?)