@ElementTypesAreNonnullByDefault
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<>(