when qtile can't found key, self.conn.get_modifire return None. So I fixed that ModMasks allow to receive None.
when qtile can't found key, self.conn.get_modifire return None.
So I fixed that ModMasks allow to receive None.

zordsdavini/qtile,frostidaho/qtile,kynikos/qtile,ramnes/qtile,tych0/qtile,de-vri-es/qtile,de-vri-es/qtile,flacjacket/qtile,cortesi/qtile,soulchainer/qtile,qtile/qtile,kynikos/qtile,cortesi/qtile,qtile/qtile,frostidaho/qtile,soulchainer/qtile,zordsdavini/qtile,ramnes/qtile,tych0/qtile,flacjacket/qtile