code: public boolean putTune(AbcTune tune) {
  		boolean ret = containsTune(tune);
  		super.putTune(tune);
  		TuneChangeEvent tce = new TuneChangeEvent(this,
  				TuneChangeEvent.TUNE_ADDED, tune);
  		if (ret) // update
  			tce.setType(TuneChangeEvent.TUNE_UPDATED);
  		notifyListenersForTuneChange(tce);
  		return ret;
  	}
docs: Put a tune into the book. If exists, replace tune with the same reference
  number and returns true. If doesn't exist, add it and return false.
  
  @param tune
  @return true if it replaced an existing tune, false otherwise