'Pick a server and port from DNS answers.
Gets DNS answers if none available.
Removes used answer from available answers.
:param domain: The domain in question.
:param port: If the results don\'t include a port, use this one.'

def pick_dns_answer(self, domain, port=None):

    if (not self.dns_answers):
        self.dns_answers = self.get_dns_records(domain, port)
    if (sys.version_info < (3, 0)):
        return self.dns_answers.next()
    else:
        return next(self.dns_answers)
