On Fri, Oct 7, 2016 at 6:36 AM, Serhiy Storchaka firstname.lastname@example.org wrote:
A number of builtin iterator classes (but not all builtin iterator classes) are registered with the Iterator ABC in Lib/_collections_abc.py. But isinstance(it, Iterable) check works without explicit registration, because Iterable has __subclasshook__ that checks iterator methods. Is there a need in explicit registrations? Or their can be safely removed?
The preferred apprach is actually inheritance; registration comes next; the __subclasshook__ is a final compromise to the tradition of duck typing. I think the registrations should stay.