*
 * <p>The time complexity of all collection-returning accessors is O(1), since views are returned.
 *
 * @author James Sexton
 * @author Joshua O'Madadhain
 * @author Omar Darwish
 * @param <N> Node parameter type
 * @param <V> Value parameter type
 */
class StandardValueGraph<N, V> extends AbstractValueGraph<N, V> {
  private final boolean isDirected;

 *
 * <p>The time complexity of all collection-returning accessors is O(1), since views are returned.
 *
 * @author James Sexton
 * @author Joshua O'Madadhain
 * @author Omar Darwish
 * @param <N> Node parameter type
 * @param <E> Edge parameter type
 */
class StandardNetwork<N, E> extends AbstractNetwork<N, E> {
  private final boolean isDirected;
  private final boolean allowsParallelEdges;

   * @since 14.0
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final <V> ImmutableMap<@NonNull E, V> toMap(Function<? super E, V> valueFunction) {
    return Maps.toMap((Iterable<@NonNull E>) getDelegate(), valueFunction);
  }

  /**
   * Creates an index {@code ImmutableListMultimap} that contains the results of applying a

   * @since 14.0
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final <V> ImmutableMap<@NonNull E, V> toMap(Function<? super E, V> valueFunction) {
    return Maps.toMap((Iterable<@NonNull E>) getDelegate(), valueFunction);
  }

  /**
   * Creates an index {@code ImmutableListMultimap} that contains the results of applying a

   * the collection operation is performed. (This differs from the {@code Collector} returned by
   * {@link java.util.stream.Collectors#toMap(java.util.function.Function,
   * java.util.function.Function) Collectors.toMap(Function, Function)}, which throws an {@code
   * IllegalStateException}.)
   *
   * @since 33.2.0 (available since 21.0 in guava-jre)
   */

   * the collection operation is performed. (This differs from the {@code Collector} returned by
   * {@link java.util.stream.Collectors#toMap(java.util.function.Function,
   * java.util.function.Function) Collectors.toMap(Function, Function)}, which throws an {@code
   * IllegalStateException}.)
   *
   * @since 21.0
   */
  public static <T extends @Nullable Object, K extends Enum<K>, V>