def addIgnore(self, hostmask, expiration=0):
        assert ircutils.isUserHostmask(hostmask), 'got %s' % hostmask
        self.ignores[hostmask] = int(expiration)
Adds an ignore to the channel ignore list.
dataset/ETHPy150Open ProgVal/Limnoria/src/ircdb.py/IrcChannel.addIgnore