code: public static <K, EV> Graph<K, NullValue, EV> fromTupleDataSet(DataSet<Tuple3<K, K, EV>> edges,
  			ExecutionEnvironment context) {
  
  		DataSet<Edge<K, EV>> edgeDataSet = edges
  			.map(new Tuple3ToEdgeMap<>())
  				.name("Type conversion");
  
  		return fromDataSet(edgeDataSet, context);
  	}
docs: Creates a graph from a DataSet of Tuple3 objects for edges.
  
  <p>The first field of the Tuple3 object will become the source ID,
  the second field will become the target ID, and the third field will become
  the edge value.
  
  <p>Vertices are created automatically and their values are set to NullValue.
  
  @param edges a DataSet of Tuple3 representing the edges.
  @param context the flink execution environment.
  @return the newly created graph.