The "Zope" interface model was proposed 21 years ago but not accepted:
Rejection Notice
I’m rejecting this PEP. It’s been five years now. While at some point I expect that Python will have interfaces, it would be naive to expect it to resemble the syntax in this PEP. Also, PEP 246 is being rejected in favor of something completely different; interfaces won’t play a role in adaptation or whatever will replace it. GvR.
---hmm, maybe someone should dust this off and give it another try...