def removeIgnore(self, hostmask):
        assert ircutils.isUserHostmask(hostmask), 'got %s' % hostmask
        return self.ignores.pop(hostmask)
Find or create a random shard and alter its `count` by the given step.
dataset/ETHPy150Open ProgVal/Limnoria/src/ircdb.py/IrcChannel.removeIgnore--crossover with--dataset/ETHPy150Open potatolondon/djangae/djangae/fields/counting.py/RelatedShardManager._update_or_create_shard