code: public static <K, VV, EV> Graph<K, VV, EV> fromCollection(Collection<Edge<K, EV>> edges,
  			final MapFunction<K, VV> vertexValueInitializer, ExecutionEnvironment context) {
  
  		return fromDataSet(context.fromCollection(edges), vertexValueInitializer, context);
  	}
docs: Creates a graph from a Collection of edges.
  Vertices are created automatically and their values are set
  by applying the provided map function to the vertex IDs.
  
  @param edges a Collection of edges.
  @param vertexValueInitializer a map function that initializes the vertex values.
  It allows to apply a map transformation on the vertex ID to produce an initial vertex value.
  @param context the flink execution environment.
  @return the newly created graph.