def test_bytesPy3(self):
        """
        Byte strings are not accceptable in Python 3.
        """
        exc = self.assertRaises(TypeError, _coercedUnicode, b'bytes')
        self.assertEqual(str(exc), "Expected str not b'bytes' (bytes)")

        Byte strings are not accceptable in Python 3.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_compat.py