return containsKey(key) ? unfiltered.removeAll(key) : unmodifiableEmptyCollection();
  }

  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)
        ? Collections.<V>emptySet()
        : Collections.<V>emptyList();
  }

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

  @Override

import com.google.common.collect.Ordering;
import com.google.common.collect.PeekingIterator;
import com.google.common.collect.Range;
import com.google.common.collect.RowSortedTable;
import com.google.common.collect.SetMultimap;
import com.google.common.collect.Sets;
import com.google.common.collect.SortedMapDifference;
import com.google.common.collect.SortedMultiset;
import com.google.common.collect.SortedSetMultimap;

  }

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

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

  @Override

import com.google.common.collect.Multiset;
import com.google.common.collect.Ordering;
import com.google.common.collect.Range;
import com.google.common.collect.RowSortedTable;
import com.google.common.collect.SetMultimap;
import com.google.common.collect.SortedMultiset;
import com.google.common.collect.Table;
import com.google.common.collect.TreeBasedTable;
import com.google.common.collect.TreeMultiset;

   * 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(@CheckForNull 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(@CheckForNull Object obj);

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.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.

      extends SynchronizedMultimap<K, V> implements SetMultimap<K, V> {
    @CheckForNull transient Set<Map.Entry<K, V>> entrySet;

    SynchronizedSetMultimap(SetMultimap<K, V> delegate, @CheckForNull Object mutex) {
      super(delegate, mutex);
    }

    @Override
    SetMultimap<K, V> delegate() {
      return (SetMultimap<K, V>) super.delegate();
    }

    @Override

      extends SynchronizedMultimap<K, V> implements SetMultimap<K, V> {
    @CheckForNull transient Set<Map.Entry<K, V>> entrySet;

    SynchronizedSetMultimap(SetMultimap<K, V> delegate, @CheckForNull Object mutex) {
      super(delegate, mutex);
    }

    @Override
    SetMultimap<K, V> delegate() {
      return (SetMultimap<K, V>) super.delegate();
    }

    @Override