code: @Pure
  	public Iterable<BusHub> busHubs() {
  		final BusStop busStop = getBusStop();
  		if (busStop != null) {
  			return busStop.busHubs();
  		}
  		return Collections.emptyList();
  	}
docs: Replies the hubs in which this bus halt is located in
  throught an associated bus stop.
  
  @return the hubs