code: def _find_supported_challenge(authzr, responders):
      
      matches = [
          (responder, challbs[0])
          for challbs in authzr.body.resolved_combinations
          for responder in responders
          if [challb.typ for challb in challbs] == [responder.challenge_type]]
      if len(matches) == 0:
          raise NoSupportedChallenges(authzr)
      else:
          return matches[0]
docs: Find a challenge combination that consists of a single challenge that the
      responder can satisfy.
  
      :param ~acme.messages.AuthorizationResource auth: The authorization to
          examine.
  
      :type responder: List[`~txacme.interfaces.IResponder`]
      :param responder: The possible responders to use.
  
      :raises NoSupportedChallenges: When a suitable challenge combination is not
          found.
  
      :rtype: Tuple[`~txacme.interfaces.IResponder`,
              `~acme.messages.ChallengeBody`]
      :return: The responder and challenge that were found.