code: def _check_for_answers(self, pk):
          
          longest_match = ()
          if len(self._answer_patterns) > 0:
              data = (pk.header,) + tuple(pk.data)
              for p in list(self._answer_patterns.keys()):
                  logger.debug('Looking for pattern match on %s vs %s', p, data)
                  if len(p) <= len(data):
                      if p == data[0:len(p)]:
                          match = data[0:len(p)]
                          if len(match) >= len(longest_match):
                              logger.debug('Found new longest match %s', match)
                              longest_match = match
          if len(longest_match) > 0:
              self._answer_patterns[longest_match].cancel()
              del self._answer_patterns[longest_match]
docs: Callback called for every packet received to check if we are
          waiting for an answer on this port. If so, then cancel the retry
          timer.