Thanks for your feedback!

Indeed this is a documentation patch describing what I could implement if a core dev gave the slightest hint that it stands a small chance of getting included. There's no point in writing code that Python core doesn't want.

I designed this API to maximize the chances it would be accepted, based on what I know of Python's development. That's probably why it was merely ignored rather than rejected ;-) More seriously, since I'm interested in improving what the stdlib ships, I have to take backwards compatibility into account. If I just wanted to implement a different API, I'd do it outside of CPython.

Yes, I could add PEP 249 compliance considerations to the docs. I'll do it if my general approach is accepted.