code: @Pure
  	public Iterator<BusHub> busHubIterator() {
  		return Iterators.unmodifiableIterator(
  				Iterators.concat(this.validBusHubs.iterator(), this.invalidBusHubs.iterator()));
  	}
docs: Replies the list of the bus hubs of the bus network.
  
  @return a list of bus hubs.