docs: public <NV> Graph<K, VV, NV> mapEdges(final MapFunction<Edge<K, EV>, NV> mapper, TypeInformation<Edge<K, NV>> returnType) {
  		DataSet<Edge<K, NV>> mappedEdges = edges.map(
  			new MapFunction<Edge<K, EV>, Edge<K, NV>>() {
  				private Edge<K, NV> output = new Edge<>();
  
  				public Edge<K, NV> map(Edge<K, EV> value) throws Exception {
  					output.f0 = value.f0;
  					output.f1 = value.f1;
  					output.f2 = mapper.map(value);
  					return output;
  				}
  			})
  			.returns(returnType)
  			.withForwardedFields("f0; f1")
  				.name("Map edges");
  
  		return new Graph<>(this.vertices, mappedEdges, this.context);
  	}