def test_filteredQuery(self):
        """
        L{Resolver._query} accepts a L{Query} instance and an address, issues
        the query, and returns a L{Deferred} which fires with the response to
        the query.  If a true value is passed for the C{filter} parameter, the
        result is a three-tuple of lists of records.
        """
        answer, authority, additional = self._queryTest(True)
        self.assertEqual(
            answer,
            [RRHeader(b'foo.example.com', payload=Record_A('5.8.13.21', ttl=0))])
        self.assertEqual(authority, [])
        self.assertEqual(additional, [])

        L{Resolver._query} accepts a L{Query} instance and an address, issues
        the query, and returns a L{Deferred} which fires with the response to
        the query.  If a true value is passed for the C{filter} parameter, the
        result is a three-tuple of lists of records.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_rootresolve.py