def test_KEXDH_REPLY(self):
        """
        Test that the KEXDH_REPLY message verifies the server.
        """
        (exchangeHash, signature, packetStart) = self.begin_KEXDH_REPLY()

        def _cbTestKEXDH_REPLY(value):
            self.assertIsNone(value)
            self.assertTrue(self.calledVerifyHostKey)
            self.assertEqual(self.proto.sessionID, exchangeHash)

        d = self.proto.ssh_KEX_DH_GEX_GROUP(
            packetStart + common.NS(signature)
        )
        d.addCallback(_cbTestKEXDH_REPLY)

        return d

        Test that the KEXDH_REPLY message verifies the server.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_transport.py