docs: public static <K, EV> DataSet<Vertex<K, NullValue>> vertexSet(DataSet<Edge<K, EV>> edges, int parallelism) {
  		DataSet<Vertex<K, NullValue>> vertexSet = edges
  			.flatMap(new EmitSrcAndTarget<>())
  				.setParallelism(parallelism)
  				.name("Emit source and target labels");
  
  		return vertexSet
  			.distinct()
  			.setCombineHint(CombineHint.HASH)
  				.setParallelism(parallelism)
  				.name("Emit vertex labels");
  	}