'Implement name lookup by recursively discovering the authoritative
server for the name and then asking it, starting at one of the servers
in C{self.hints}.'

def _lookup(self, name, cls, type, timeout):

    if (timeout is None):
        timeout = (1, 3, 11, 45)
    return self._discoverAuthority(dns.Query(name, type, cls), self._roots(), timeout, self._maximumQueries)
