Method fail

tests/test_private_attributes.py:527–530

(obj)

            delete_calls.append(obj)

            def fail(obj):
                # I have purposely not used the exact formatting you'd get if the attribute wasn't defined,
                # to make it clear this function is being called, while also having sensible behavior
                raise AttributeError(f'{self.name!r} is not defined on {obj!r}')

            self.fn = fail