return delegate.pollFirst();
  }

  @Override
  public @Nullable E pollLast() {
    return delegate.pollLast();
  }

  @Override
  public boolean remove(Object object) {
    return delegate.remove(checkValid(object));
  }

  @Override
  public boolean removeAll(Collection<?> c) {
    return delegate.removeAll(c);
  }

  @Override

  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testPropagatesRemoveLastElementToMultimap() {
    Collection<V> result = multimap().asMap().get(k0());
    assertTrue(result.remove(v0()));
    assertGet(k0());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testPropagatesClearToMultimap() {

  // TODO(b/192446998): Remove this override after tools understand nullness better.
  @CheckForNull
  public V put(K key, @ParametricNullness V value) {
    return super.put(key, value);
  }

  @CanIgnoreReturnValue
  @Override
  @SuppressWarnings("RedundantOverride") // b/192446478: RedundantOverride ignores some annotations.
  // TODO(b/192446998): Remove this override after tools understand nullness better.

    bimap.put(1, "one");
    bimap.put(2, "two");
    bimap.put(3, "three");
    Iterator<Integer> iterator = bimap.keySet().iterator();
    iterator.next();
    iterator.next();
    iterator.remove();
    iterator.next();
    iterator.remove();
    assertEquals(1, bimap.size());
    assertEquals(1, bimap.inverse().size());
  }

  @SuppressWarnings("IdentityHashMapBoxing") // explicitly testing IdentityHashMap

    assertFalse(multimap().entries().contains(Helpers.mapEntry(k0(), null)));
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemovePropagatesToMultimap() {
    assertTrue(multimap().entries().remove(Helpers.mapEntry(k0(), v0())));
    expectMissing(Helpers.mapEntry(k0(), v0()));
    assertEquals(getNumElements() - 1, multimap().size());

  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testKeysRemove() {
    int original = multimap().keys().remove(k0(), 1);
    assertEquals(Math.max(original - 1, 0), multimap().get(k0()).size());
  }

  @CollectionSize.Require(ONE)
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
  public void testKeysEntrySetIteratorRemove() {
    Multiset<K> keys = multimap().keys();

  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testKeysRemove() {
    int original = multimap().keys().remove(k0(), 1);
    assertEquals(Math.max(original - 1, 0), multimap().get(k0()).size());
  }

  @CollectionSize.Require(ONE)
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
  public void testKeysEntrySetIteratorRemove() {
    Multiset<K> keys = multimap().keys();

public class MultimapRemoveAllTester<K, V> extends AbstractMultimapTester<K, V, Multimap<K, V>> {
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAllAbsentKey() {
    assertEmpty(multimap().removeAll(k3()));
    expectUnchanged();
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAllPresentKey() {
    assertContentsAnyOrder(multimap().removeAll(k0()), v0());

  SUPPORTS_REMOVE_WITH_INDEX(CollectionFeature.SUPPORTS_REMOVE),

  GENERAL_PURPOSE(
      CollectionFeature.GENERAL_PURPOSE,
      SUPPORTS_SET,
      SUPPORTS_ADD_WITH_INDEX,
      SUPPORTS_REMOVE_WITH_INDEX),

  /** Features supported by lists where only removal is allowed. */
  REMOVE_OPERATIONS(CollectionFeature.REMOVE_OPERATIONS, SUPPORTS_REMOVE_WITH_INDEX);

  SUPPORTS_ADD,
  SUPPORTS_REMOVE,
  SUPPORTS_ITERATOR_REMOVE,
  FAILS_FAST_ON_CONCURRENT_MODIFICATION,

  /**
   * Features supported by general-purpose collections - everything but {@link #RESTRICTS_ELEMENTS}.
   *
   * @see java.util.Collection the definition of general-purpose collections.
   */
  GENERAL_PURPOSE(SUPPORTS_ADD, SUPPORTS_REMOVE, SUPPORTS_ITERATOR_REMOVE),