def test_zoneTransfer(self):
        """
        Test DNS 'AXFR' queries (Zone transfer)
        """
        default_ttl = soa_record.expire
        results = [copy.copy(r) for r in reduce(operator.add, test_domain_com.records.values())]
        for r in results:
            if r.ttl is None:
                r.ttl = default_ttl
        return self.namesTest(
            self.resolver.lookupZone('test-domain.com').addCallback(lambda r: (r[0][:-1],)),
            results
        )

        Test DNS 'AXFR' queries (Zone transfer)
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_names.py