final Multimap<K, V> unfiltered;
  final Predicate<? super Entry<K, V>> predicate;

  FilteredEntryMultimap(Multimap<K, V> unfiltered, Predicate<? super Entry<K, V>> predicate) {
    this.unfiltered = checkNotNull(unfiltered);
    this.predicate = checkNotNull(predicate);
  }

  @Override
  public Multimap<K, V> unfiltered() {
    return unfiltered;
  }

  @Override

      Multimap<K, V> unfiltered, Predicate<? super K> keyPredicate) {
    if (unfiltered instanceof SetMultimap) {
      return filterKeys((SetMultimap<K, V>) unfiltered, keyPredicate);
    } else if (unfiltered instanceof ListMultimap) {
      return filterKeys((ListMultimap<K, V>) unfiltered, keyPredicate);
    } else if (unfiltered instanceof FilteredKeyMultimap) {

      Multimap<K, V> unfiltered, Predicate<? super K> keyPredicate) {
    if (unfiltered instanceof SetMultimap) {
      return filterKeys((SetMultimap<K, V>) unfiltered, keyPredicate);
    } else if (unfiltered instanceof ListMultimap) {
      return filterKeys((ListMultimap<K, V>) unfiltered, keyPredicate);
    } else if (unfiltered instanceof FilteredKeyMultimap) {

    extends FilteredEntryMultimap<K, V> implements FilteredSetMultimap<K, V> {

  FilteredEntrySetMultimap(SetMultimap<K, V> unfiltered, Predicate<? super Entry<K, V>> predicate) {
    super(unfiltered, predicate);
  }

  @Override
  public SetMultimap<K, V> unfiltered() {
    return (SetMultimap<K, V>) unfiltered;
  }

  @Override
  public Set<V> get(@ParametricNullness K key) {
    return (Set<V>) super.get(key);
  }

    extends FilteredKeyMultimap<K, V> implements FilteredSetMultimap<K, V> {

  FilteredKeySetMultimap(SetMultimap<K, V> unfiltered, Predicate<? super K> keyPredicate) {
    super(unfiltered, keyPredicate);
  }

  @Override
  public SetMultimap<K, V> unfiltered() {
    return (SetMultimap<K, V>) unfiltered;
  }

  @Override
  public Set<V> get(@ParametricNullness K key) {
    return (Set<V>) super.get(key);
  }

    extends FilteredKeyMultimap<K, V> implements ListMultimap<K, V> {
  FilteredKeyListMultimap(ListMultimap<K, V> unfiltered, Predicate<? super K> keyPredicate) {
    super(unfiltered, keyPredicate);
  }

  @Override
  public ListMultimap<K, V> unfiltered() {
    return (ListMultimap<K, V>) super.unfiltered();
  }

  @Override
  public List<V> get(@ParametricNullness K key) {
    return (List<V>) super.get(key);
  }

    extends FilteredKeyMultimap<K, V> implements FilteredSetMultimap<K, V> {

  FilteredKeySetMultimap(SetMultimap<K, V> unfiltered, Predicate<? super K> keyPredicate) {
    super(unfiltered, keyPredicate);
  }

  @Override
  public SetMultimap<K, V> unfiltered() {
    return (SetMultimap<K, V>) unfiltered;
  }

  @Override
  public Set<V> get(@ParametricNullness K key) {
    return (Set<V>) super.get(key);
  }

                Set<String> unfiltered = new LinkedHashSet<>();
                unfiltered.add("yyy");
                unfiltered.addAll(ImmutableList.copyOf(elements));
                unfiltered.add("zzz");
                unfiltered.add("abc");
                return Sets.filter(
                    Sets.filter(unfiltered, Collections2Test.LENGTH_1),
                    Collections2Test.NOT_YYY_ZZZ);

  @Override
  public boolean removeAll(Collection<?> c) {
    return Iterables.removeIf(
        multimap.unfiltered().entries(),
        and(multimap.entryPredicate(), valuePredicateOnEntries(in(c))));
  }

  @Override
  public boolean retainAll(Collection<?> c) {
    return Iterables.removeIf(
        multimap.unfiltered().entries(),
        and(multimap.entryPredicate(), valuePredicateOnEntries(not(in(c)))));
  }

  @Override

import org.jspecify.annotations.Nullable;

/**
 * A supertype for filtered {@link SetMultimap} implementations.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
interface FilteredSetMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends FilteredMultimap<K, V>, SetMultimap<K, V> {
  @Override
  SetMultimap<K, V> unfiltered();