Function<? super T, ? extends V> valueFunction,
          BinaryOperator<V> mergeFunction,
          Supplier<I> tableSupplier) {
    checkNotNull(rowFunction);
    checkNotNull(columnFunction);
    checkNotNull(valueFunction);
    checkNotNull(mergeFunction);
    checkNotNull(tableSupplier);
    return Collector.of(
        tableSupplier,
        (table, input) ->
            mergeTables(
                table,

    return new SimpleTimeLimiter(executor);
  }

  @Override
  public <T> T newProxy(
      T target, Class<T> interfaceType, long timeoutDuration, TimeUnit timeoutUnit) {
    checkNotNull(target);
    checkNotNull(interfaceType);
    checkNotNull(timeoutUnit);
    checkPositiveTimeout(timeoutDuration);
    checkArgument(interfaceType.isInterface(), "interfaceType must be an interface type");

          Function<? super T, ? extends V> valueFunction,
          BinaryOperator<V> mergeFunction,
          Supplier<I> tableSupplier) {
    checkNotNull(rowFunction);
    checkNotNull(columnFunction);
    checkNotNull(valueFunction);
    checkNotNull(mergeFunction);
    checkNotNull(tableSupplier);
    return Collector.of(
        tableSupplier,
        (table, input) ->
            mergeTables(
                table,

  @J2ktIncompatible
  @GwtIncompatible
  public static <T extends @Nullable Object> AsyncCallable<T> asAsyncCallable(
      Callable<T> callable, ListeningExecutorService listeningExecutorService) {
    checkNotNull(callable);
    checkNotNull(listeningExecutorService);
    return () -> listeningExecutorService.submit(callable);
  }

  /**
   * Wraps the given callable such that for the duration of {@link Callable#call} the thread that is

  MapIteratorCache(Map<K, V> backingMap) {
    this.backingMap = checkNotNull(backingMap);
  }

  @CanIgnoreReturnValue
  final @Nullable V put(K key, V value) {
    checkNotNull(key);
    checkNotNull(value);
    clearCache();
    return backingMap.put(key, value);
  }

  @CanIgnoreReturnValue
  final @Nullable V remove(Object key) {
    checkNotNull(key);
    clearCache();
    return backingMap.remove(key);
  }

  }

  @Override
  public T or(T defaultValue) {
    return checkNotNull(defaultValue, "use Optional.orNull() instead of Optional.or(null)");
  }

  @SuppressWarnings("unchecked") // safe covariant cast
  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {
    return (Optional<T>) checkNotNull(secondChoice);
  }

  @Override
  public T or(Supplier<? extends T> supplier) {

    return connections;
  }

  @Override
  @CanIgnoreReturnValue
  public @Nullable V putEdgeValue(N nodeU, N nodeV, V value) {
    checkNotNull(nodeU, "nodeU");
    checkNotNull(nodeV, "nodeV");
    checkNotNull(value, "value");

    if (!allowsSelfLoops()) {
      checkArgument(!nodeU.equals(nodeV), SELF_LOOPS_NOT_ALLOWED, nodeU);
    }

  SingletonImmutableBiMap(K key, V value) {
    super(singletonMap(checkNotNull(key), checkNotNull(value)));
    this.singleKey = key;
    this.singleValue = value;
  }

  private SingletonImmutableBiMap(K key, V value, SingletonImmutableBiMap<V, K> inverse) {
    super(singletonMap(checkNotNull(key), checkNotNull(value)));
    this.singleKey = key;
    this.singleValue = value;
    this.inverse = inverse;

    return connections;
  }

  @Override
  @CanIgnoreReturnValue
  public boolean addEdge(N nodeU, N nodeV, E edge) {
    checkNotNull(nodeU, "nodeU");
    checkNotNull(nodeV, "nodeV");
    checkNotNull(edge, "edge");

    if (containsEdge(edge)) {
      EndpointPair<N> existingIncidentNodes = incidentNodes(edge);

  @CanIgnoreReturnValue // TODO(kak): consider removing this
  @Override
  public <T> T newProxy(
      T target, Class<T> interfaceType, long timeoutDuration, TimeUnit timeoutUnit) {
    checkNotNull(target);
    checkNotNull(interfaceType);
    checkNotNull(timeoutUnit);
    return target; // ha ha
  }

  @CanIgnoreReturnValue // TODO(kak): consider removing this
  @Override
  @ParametricNullness