}

      for (N predecessor : sanityCheckSet(graph.predecessors(node))) {
        assertThat(graph.successors(predecessor)).contains(node);
        assertThat(graph.hasEdgeConnecting(predecessor, node)).isTrue();
        assertThat(graph.incidentEdges(node)).contains(EndpointPair.of(graph, predecessor, node));
      }

      for (N successor : sanityCheckSet(graph.successors(node))) {

      }

      for (N predecessor : sanityCheckSet(graph.predecessors(node))) {
        assertThat(graph.successors(predecessor)).contains(node);
        assertThat(graph.hasEdgeConnecting(predecessor, node)).isTrue();
        assertThat(graph.incidentEdges(node)).contains(EndpointPair.of(graph, predecessor, node));
      }

      for (N successor : sanityCheckSet(graph.successors(node))) {

      }

      for (N predecessor : sanityCheckSet(network.predecessors(node))) {
        assertThat(network.successors(predecessor)).contains(node);
        assertThat(network.edgesConnecting(predecessor, node)).isNotEmpty();
      }

      for (N successor : sanityCheckSet(network.successors(node))) {
        assertThat(network.predecessors(successor)).contains(node);

      }

      for (N predecessor : sanityCheckSet(network.predecessors(node))) {
        assertThat(network.successors(predecessor)).contains(node);
        assertThat(network.edgesConnecting(predecessor, node)).isNotEmpty();
      }

      for (N successor : sanityCheckSet(network.successors(node))) {
        assertThat(network.predecessors(successor)).contains(node);