def referring_exs(self, answer, max_count=5):
        for ii in self._refex_lookup[answer]:
            if self._refex_count[ii] < max_count:
                yield ii
Called when a request is sent to this channel.  By default it delegates
dataset/ETHPy150Open Pinafore/qb/extractors/mentions.py/Mentions.referring_exs--crossover with--dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/conch/ssh/channel.py/SSHChannel.requestReceived