code: public Graph<K, VV, EV> filterOnEdges(FilterFunction<Edge<K, EV>> edgeFilter) {
  		DataSet<Edge<K, EV>> filteredEdges = this.edges.filter(edgeFilter).name("Filter on edges");
  
  		return new Graph<>(this.vertices, filteredEdges, this.context);
  	}
docs: Apply a filtering function to the graph and return a sub-graph that
  satisfies the predicates only for the edges.
  
  @param edgeFilter the filter function for edges.
  @return the resulting sub-graph.