def test_emptyHash(self):
        """
        C{__hash__} can be used to get a hash of an address, even one referring
        to L{None} rather than a real path.
        """
        addr = self.buildAddress()
        d = {addr: True}
        self.assertTrue(d[self.buildAddress()])

        C{__hash__} can be used to get a hash of an address, even one referring
        to L{None} rather than a real path.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_address.py