@Override
		public int compare(Set lhs, Set rhs) {
			Iterator<State> li = lhs.iterator();
			Iterator<State> ri = rhs.iterator();
			while (li.hasNext() && ri.hasNext()) {
				int res = li.next().compareTo(ri.next());
				if (res != 0)
					return res;
			}
			if (li.hasNext())
				return 1;
			if (ri.hasNext())
				return -1;
			return 0;
		}