code: @Pure
  	public Iterable<BusItineraryHalt> busHalts() {
  		final MultiCollection<BusItineraryHalt> halts = new MultiCollection<>();
  		halts.addCollection(this.validHalts);
  		halts.addCollection(this.invalidHalts);
  		return Collections.unmodifiableCollection(halts);
  	}
docs: Replies the list of the bus halts of the bus itinerary.
  
  @return a list of bus halts