"faux-immutability" is a good way to describe it. My problem is the "faux"; proper immutability is virtually impossible in python and I'm not convinced about providing partial immutability and thereby giving people a false sense of security. That said there's an issue about it: https://github.com/samuelcolvin/pydantic/issues/38. I'll consider it if we can find a performant and elegant way of using it.

__eq__ makes sense, I'll do it when I get round to it

__hash__ would be nice but far from simple to do in a performant way.

__lt__ I'm not sure what this would mean?

__cmp__ no longer exists in python 3.