Hmm, IDK.

Stuff like @attr.ib is kind of cute looking. (This not being a good thing).

Though in reality, I'd probably want more explicit methods. If you are using something like Django REST framework, you can validate with the serializer. And sometimes you want to validate (often) the combination of variables and how they interact.

Kind of feels a little non-pythonic to me. Clever, but the ways it is changing things are stuff you have to unroll if the behavior grows, versus stuff you just add to.