/** A skeleton implementation for {@link SortedMultiset#elementSet}. */
  @SuppressWarnings("JdkObsolete") // TODO(b/6160855): Switch GWT emulations to NavigableSet.
  static class ElementSet<E extends @Nullable Object> extends Multisets.ElementSet<E>
      implements SortedSet<E> {
    @Weak private final SortedMultiset<E> multiset;

    ElementSet(SortedMultiset<E> multiset) {
      this.multiset = multiset;
    }

   *
   * @since 22.0
   */
  public static <T extends @Nullable Object, E>
      Collector<T, ?, ImmutableSortedMultiset<E>> toImmutableSortedMultiset(
          Comparator<? super E> comparator,
          Function<? super T, ? extends E> elementFunction,
          ToIntFunction<? super T> countFunction) {
    checkNotNull(comparator);
    checkNotNull(elementFunction);

    public String toString() {
      return "another arbitrary string";
    }
  }

  private static class SubHandler1 extends DelegatingInvocationHandlerWithEquals {
    SubHandler1(Object delegate) {
      super(delegate);
    }
  }

  private static class SubHandler2 extends DelegatingInvocationHandlerWithEquals {
    SubHandler2(Object delegate) {
      super(delegate);
    }
  }

   * always true when the iterable has fewer than two elements.
   */
  public static <T extends @Nullable Object> boolean isInOrder(
      Iterable<? extends T> iterable, Comparator<T> comparator) {
    checkNotNull(comparator);
    Iterator<? extends T> it = iterable.iterator();
    if (it.hasNext()) {
      T prev = it.next();
      while (it.hasNext()) {
        T next = it.next();

        final V value = parent.remove(key);
        if (value != null) {
            return value;
        }
        return parent.remove(key);
    }

    @Override
    public void putAll(final Map<? extends K, ? extends V> m) {
        parent.putAll(m);
    }

    @Override
    public void clear() {
        parent.clear();
    }

    @Override
    public Set<K> keySet() {

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@NullMarked
public abstract class AbstractMultimapTester<
        K extends @Nullable Object, V extends @Nullable Object, M extends Multimap<K, V>>
    extends AbstractContainerTester<M, Entry<K, V>> {

  private M multimap;

  protected M multimap() {
    return multimap;
  }

  /**

    assertSame(map, ImmutableClassToInstanceMap.copyOf(map));
  }

  public void testCopyOf_map_nulls() {
    Map<Class<? extends Number>, Number> nullKey = singletonMap(null, (Number) 1.0);
    assertThrows(NullPointerException.class, () -> ImmutableClassToInstanceMap.copyOf(nullKey));

    Map<? extends Class<? extends Number>, Number> nullValue = singletonMap(Number.class, null);

 * implementation.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible
public class MultimapTestSuiteBuilder<K, V, M extends Multimap<K, V>>
    extends PerCollectionSizeTestSuiteBuilder<
        MultimapTestSuiteBuilder<K, V, M>, TestMultimapGenerator<K, V, M>, M, Entry<K, V>> {

  public static <K, V, M extends Multimap<K, V>> MultimapTestSuiteBuilder<K, V, M> using(
      TestMultimapGenerator<K, V, M> generator) {

            return new ApiResult(this);
        }
    }

    /**
     * Represents an API response for an update operation.
     */
    public static class ApiUpdateResponse extends ApiResponse {
        /** The ID of the updated item. */
        protected String id;
        /** Whether the item was created (true) or updated (false). */
        protected boolean created;

        /**

 *
 * @author Louis Wasserman
 */
@GwtCompatible
abstract class TransformedIterator<F extends @Nullable Object, T extends @Nullable Object>
    implements Iterator<T> {
  final Iterator<? extends F> backingIterator;

  TransformedIterator(Iterator<? extends F> backingIterator) {
    this.backingIterator = checkNotNull(backingIterator);
  }

  @ParametricNullness