code: func (st *stateTracker) IsOn(c, n string) (*ChanPrivs, bool) {
  	st.mu.Lock()
  	defer st.mu.Unlock()
  	nk, nok := st.nicks[n]
  	ch, cok := st.chans[c]
  	if nok && cok {
  		return nk.isOn(ch)
  	}
  	return nil, false
  }
docs: // Returns true if both the channel c and the nick n are tracked
  // and the nick is associated with the channel.