'Send/Receive confirmation of all challenges.
.. note:: This method also cleans up the auth_handler state.'

def _respond(self, resp, best_effort):

    chall_update = dict()
    active_achalls = self._send_responses(self.achalls, resp, chall_update)
    try:
        self._poll_challenges(chall_update, best_effort)
    finally:
        self._cleanup_challenges(active_achalls)
