Node node6 = graphModel.factory().newNode("5");
Node node7 = graphModel.factory().newNode("6");
undirectedGraph.addNode(node1);
undirectedGraph.addNode(node2);
undirectedGraph.addNode(node3);
undirectedGraph.addNode(node4);
undirectedGraph.addNode(node5);
undirectedGraph.addNode(node6);
undirectedGraph.addNode(node7);
Edge edge12 = graphModel.factory().newEdge(node1, node2, false);
Edge edge13 = graphModel.factory().newEdge(node1, node3, false);