> That's just what I'd like and I suppose can't be currently done with > current ABC, PyProtocols or zope.interface implementations, right?
It can. With __instancecheck__ you can override isinstance. It is possible (for example) to write a subclass of abc.ABCMeta, which extends __instancecheck__ to use an _instancehook classmethod similarly to __subclasshook__. Then in your MyInterface class you can implement _instancehook to check for methods/signatures/whatever you want. Daniel -- http://mail.python.org/mailman/listinfo/python-list
