The ‘hash’ method can be removed

If a class implements both ‘eq’ and ‘hash’, it's important for those implementations to be consistent with each other:

a == b ⇔ hash(a) == hash(b)

TIL that Python will try to help you adhere to this constraint in the presence of subclasses. If you define a subclass, and implement ‘eq’ but not ‘hash’, then Python will implicitly set ‘hash’ to ‘None’ in that class. That way you can't accidentally override the meaning of “equals” in a way that breaks hashability.

=> ‘object.hash’ documentation

This has some ramifications with the type system:

=> ‘hash’, ‘eq’, and LSP [Python Discourse]

=> » Languages » Python