Given

class MyClass:
    def __eq__(self, other):
        return True

    __hash__ = None

Running ruff --isolated --select PLW1641 with Ruff 0.0.285:

x.py:1:7: PLW1641 Object does not implement `__hash__` method

While the purpose of PLW1641 is exactly to check for when __eq__ is defined and __hash__ is None (the default when __eq__ is defined but __hash__ is not), I think that if the code explicitly sets __hash__ = None then the lint should not trigger since the programmer explicitly asks for it.