def test_toMessageCopiesSections(self):
        """
        L{dns._EDNSMessage.toStr} makes no in place changes to the message
        instance.
        """
        ednsMessage = dns._EDNSMessage(ednsVersion=1)
        ednsMessage.toStr()
        self.assertEqual(ednsMessage.additional, [])

        L{dns._EDNSMessage.toStr} makes no in place changes to the message
        instance.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_dns.py