Short question. Checking if a protocol is set up? Many python improvements are changes to classes that implement a protocol. There are things you can do to make your own classes work with the protocol by setting various dunder variables like __iter__, __next__ and writing appropriate ode including throwing the right error class when done. Similarly the "with" statement works with objects that implement __enter__ and __exit__. There can be plenty of others like this and more can be anticipated in the future.
So, several related questions. Tools that help a developer add appropriate things to an object to implement the protocol or to test if it was done right. Perhaps a function with a name like is_iterable() that tells if the protocol can be applied. For the specific case of an iterable, I found something that seems to work for at least some cases: from collections import Iterable item = [1, 2, 3, 4] isinstance(item, Iterable) Not sure if it would work on one I created that did the right things or what it checks. I am interested in a pointer to something that describes many of the known protocols or extensions and maybe to modules designed sort of as I said above. I am aware some protocols may be not-quite standard with parts of the protocol embedded in different objects like wrappers or objects returned upon a request to have a proxy and many other techniques that seem to abound and allow multiple layers of indirection or seemingly almost magical as in multiple inheritance drop-ins and so on. That is what may make these things harder if someone uses something like __getattr__ or descriptors to intercept calls and provide the functionality without any actual sign of the dunder key normally expected. And, yes, I am aware of a tried and true method called try ... except ... to see if it seems to work. -- https://mail.python.org/mailman/listinfo/python-list
