}

      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);