suite.addTest(
        SortedSetMultimapTestSuiteBuilder.using(
                new TestStringSetMultimapGenerator() {
                  @Override
                  protected SetMultimap<String, String> create(Entry<String, String>[] entries) {
                    SetMultimap<String, String> multimap =
                        TreeMultimap.create(
                            Ordering.natural().nullsFirst(), Ordering.natural().nullsFirst());

  }

  @SuppressWarnings("EmptyList") // ImmutableList doesn't support nullable element types
  Collection<V> unmodifiableEmptyCollection() {
    if (unfiltered instanceof SetMultimap) {
      return emptySet();
    } else {
      return emptyList();
    }
  }

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

  @Override
  Set<K> createKeySet() {

  }

  @SuppressWarnings("EmptyList") // ImmutableList doesn't support nullable element types
  Collection<V> unmodifiableEmptyCollection() {
    if (unfiltered instanceof SetMultimap) {
      return emptySet();
    } else {
      return emptyList();
    }
  }

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

  @Override
  Set<K> createKeySet() {

  Collection<V> unmodifiableEmptyCollection() {
    // These return false, rather than throwing a UOE, on remove calls.
    return (unfiltered instanceof SetMultimap) ? emptySet() : emptyList();
  }

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

  @Override
  public Collection<V> get(@ParametricNullness K key) {

 * ListMultimap} and {@link SetMultimap}. These take their names from the fact that the collections
 * they return from {@code get} behave like (and, of course, implement) {@link List} and {@link
 * Set}, respectively.
 *
 * <p>For example, the "presidents" code snippet above used a {@code ListMultimap}; if it had used a
 * {@code SetMultimap} instead, two presidents would have vanished, and last names might or might

  Collection<V> unmodifiableEmptyCollection() {
    // These return false, rather than throwing a UOE, on remove calls.
    return (unfiltered instanceof SetMultimap) ? emptySet() : emptyList();
  }

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

  @Override
  public Collection<V> get(@ParametricNullness K key) {

import java.util.stream.Collector;
import java.util.stream.Stream;
import org.jspecify.annotations.Nullable;

/**
 * A {@link SetMultimap} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * <p><b>Warning:</b> As in all {@link SetMultimap}s, do not modify either a key <i>or a value</i>
 * of a {@code ImmutableSetMultimap} in a way that affects its {@link Object#equals} behavior.

   * in the same order. If the value orderings disagree, the multimaps will not be considered equal.
   *
   * <p>An empty {@code ListMultimap} is equal to any other empty {@code Multimap}, including an
   * empty {@code SetMultimap}.
   */
  @Override
  boolean equals(@Nullable Object obj);

   * in the same order. If the value orderings disagree, the multimaps will not be considered equal.
   *
   * <p>An empty {@code ListMultimap} is equal to any other empty {@code Multimap}, including an
   * empty {@code SetMultimap}.
   */
  @Override
  boolean equals(@Nullable Object obj);

  @MapFeature.Require(SUPPORTS_REMOVE)
  /*
   * We are comparing Multimaps of the same type, so as long as they have value collections that
   * implement equals() (as with ListMultimap or SetMultimap, as opposed to a QueueMultimap or
   * something), our equality check is value-based.
   */
  @SuppressWarnings("UndefinedEquals")
  public void testRetainAllPropagatesToMultimap() {