code: func (nk *nick) delChannel(ch *channel) {
  	if _, ok := nk.chans[ch]; ok {
  		delete(nk.chans, ch)
  		delete(nk.lookup, ch.name)
  	} else {
  		logging.Warn("Nick.delChannel(): %s not on %s.", nk.nick, ch.name)
  	}
  }
docs: // Disassociates a Channel from a Nick.