*/
final class DirectedMultiNetworkConnections<N, E> extends AbstractDirectedNetworkConnections<N, E> {

  private DirectedMultiNetworkConnections(
      Map<E, N> inEdges, Map<E, N> outEdges, int selfLoopCount) {
    super(inEdges, outEdges, selfLoopCount);
  }

  static <N, E> DirectedMultiNetworkConnections<N, E> of() {
    return new DirectedMultiNetworkConnections<>(

 */
final class DirectedMultiNetworkConnections<N, E> extends AbstractDirectedNetworkConnections<N, E> {

  private DirectedMultiNetworkConnections(
      Map<E, N> inEdges, Map<E, N> outEdges, int selfLoopCount) {
    super(inEdges, outEdges, selfLoopCount);
  }

  static <N, E> DirectedMultiNetworkConnections<N, E> of() {
    return new DirectedMultiNetworkConnections<>(

  }

  static <N, E> DirectedNetworkConnections<N, E> ofImmutable(
      Map<E, N> inEdges, Map<E, N> outEdges, int selfLoopCount) {
    return new DirectedNetworkConnections<>(
        ImmutableBiMap.copyOf(inEdges), ImmutableBiMap.copyOf(outEdges), selfLoopCount);
  }

  @Override
  public Set<N> predecessors() {

  }

  static <N, E> DirectedNetworkConnections<N, E> ofImmutable(
      Map<E, N> inEdges, Map<E, N> outEdges, int selfLoopCount) {
    return new DirectedNetworkConnections<>(
        ImmutableBiMap.copyOf(inEdges), ImmutableBiMap.copyOf(outEdges), selfLoopCount);
  }

  @Override
  public Set<N> predecessors() {

    return delegate().successors(node);
  }

  @Override
  public Set<E> incidentEdges(N node) {
    return delegate().incidentEdges(node);
  }

  @Override
  public Set<E> inEdges(N node) {
    return delegate().inEdges(node);
  }

  @Override
  public Set<E> outEdges(N node) {
    return delegate().outEdges(node);
  }

  @Override
  public EndpointPair<N> incidentNodes(E edge) {

    return adjacentNodes();
  }

  @Override
  public Set<E> incidentEdges() {
    return Collections.unmodifiableSet(incidentEdgeMap.keySet());
  }

  @Override
  public Set<E> inEdges() {
    return incidentEdges();
  }

  @Override
  public Set<E> outEdges() {
    return incidentEdges();
  }

  @Override
  public N adjacentNode(E edge) {

    }

    @Override
    public Set<E> incidentEdges(N node) {
      return network.incidentEdges(node);
    }

    @Override
    public Set<E> inEdges(N node) {
      return network.inEdges(node);
    }

    @Override
    public Set<E> outEdges(N node) {
      return network.outEdges(node);
    }

    @Override
    public EndpointPair<N> incidentNodes(E edge) {

      }

      @Override
      public boolean contains(@Nullable Object obj) {
        return inEdgeMap.containsKey(obj) || outEdgeMap.containsKey(obj);
      }
    };
  }

  @Override
  public Set<E> inEdges() {
    return Collections.unmodifiableSet(inEdgeMap.keySet());
  }

  @Override
  public Set<E> outEdges() {
    return Collections.unmodifiableSet(outEdgeMap.keySet());
  }

  @Override

 * @param <E> Edge parameter type
 */
interface NetworkConnections<N, E> {

  Set<N> adjacentNodes();

  Set<N> predecessors();

  Set<N> successors();

  Set<E> incidentEdges();

  Set<E> inEdges();

  Set<E> outEdges();

  /**
   * Returns the set of edges connecting the origin node to {@code node}. For networks without
   * parallel edges, this set cannot be of size greater than one.
   */

    return adjacentNodes();
  }

  @Override
  public Set<E> incidentEdges() {
    return Collections.unmodifiableSet(incidentEdgeMap.keySet());
  }

  @Override
  public Set<E> inEdges() {
    return incidentEdges();
  }

  @Override
  public Set<E> outEdges() {
    return incidentEdges();
  }

  @Override
  public N adjacentNode(E edge) {