}

  @Override
  public boolean containsEntry(@Nullable Object key, @Nullable Object value) {
    return delegate().containsEntry(key, value);
  }

  @Override
  public boolean containsKey(@Nullable Object key) {
    return delegate().containsKey(key);
  }

  @Override
  public boolean containsValue(@Nullable Object value) {
    return delegate().containsValue(value);
  }

  @Override

    assertFalse(multimap().containsKey(k0()));
    assertFalse(multimap().containsEntry(k0(), v0()));
    assertEmpty(result);

    assertTrue(result.add(v1()));
    assertTrue(result.add(v2()));

    assertContentsAnyOrder(result, v1(), v2());
    assertContentsAnyOrder(multimap().get(k0()), v1(), v2());
    assertTrue(multimap().containsKey(k0()));
    assertFalse(multimap().containsEntry(k0(), v0()));

    }

    @Override
    public void clear() {
      assertTrue(Thread.holdsLock(mutex));
      super.clear();
    }

    @Override
    public boolean containsKey(Object key) {
      assertTrue(Thread.holdsLock(mutex));
      return super.containsKey(key);
    }

    @Override
    public boolean containsValue(Object value) {
      assertTrue(Thread.holdsLock(mutex));
      return super.containsValue(value);
    }

  @CollectionSize.Require(absent = ZERO)
  public void testHeadMapExclusive() {
    assertFalse(navigableMap.headMap(a.getKey()).containsKey(a.getKey()));
  }

  @CollectionSize.Require(absent = ZERO)
  public void testTailMapInclusive() {
    assertTrue(navigableMap.tailMap(a.getKey()).containsKey(a.getKey()));
  }

  public void testHeadMap() {
    List<Entry<K, V>> entries =
        copyToList(

    }

    @Override
    public void clear() {
      assertTrue(Thread.holdsLock(mutex));
      super.clear();
    }

    @Override
    public boolean containsKey(Object key) {
      assertTrue(Thread.holdsLock(mutex));
      return super.containsKey(key);
    }

    @Override
    public boolean containsValue(Object value) {
      assertTrue(Thread.holdsLock(mutex));
      return super.containsValue(value);
    }

      this.rowKey = checkNotNull(rowKey);
    }

    @Nullable Map<C, V> backingRowMap;

    final void updateBackingRowMapField() {
      if (backingRowMap == null || (backingRowMap.isEmpty() && backingMap.containsKey(rowKey))) {
        backingRowMap = computeBackingRowMap();
      }
    }

    @Nullable Map<C, V> computeBackingRowMap() {
      return backingMap.get(rowKey);
    }

@SuppressWarnings("rawtypes") // maybe avoidable if we rework the whole package?
@GwtCompatible
public enum MapFeature implements Feature<Map> {
  /**
   * The map does not throw {@code NullPointerException} on calls such as {@code containsKey(null)},
   * {@code get(null)}, {@code keySet().contains(null)} or {@code remove(null)}.
   */
  ALLOWS_NULL_KEY_QUERIES,
  ALLOWS_NULL_KEYS(ALLOWS_NULL_KEY_QUERIES),
  /**

    assertFalse(multimap().containsKey(k0()));
    assertFalse(multimap().containsEntry(k0(), v0()));
    assertEmpty(result);

    assertTrue(result.add(v1()));
    assertTrue(result.add(v2()));

    assertContentsAnyOrder(result, v1(), v2());
    assertContentsAnyOrder(multimap().get(k0()), v1(), v2());
    assertTrue(multimap().containsKey(k0()));
    assertFalse(multimap().containsEntry(k0(), v0()));

  }

  @Override
  public boolean containsKey(@Nullable Object key) {
    if (unfiltered.containsKey(key)) {
      @SuppressWarnings("unchecked") // k is equal to a K, if not one itself
      K k = (K) key;
      return keyPredicate.apply(k);
    }
    return false;
  }

  @Override
  public Collection<V> removeAll(@Nullable Object key) {

  }

  @Override
  public boolean containsKey(@Nullable Object key) {
    if (unfiltered.containsKey(key)) {
      @SuppressWarnings("unchecked") // k is equal to a K, if not one itself
      K k = (K) key;
      return keyPredicate.apply(k);
    }
    return false;
  }

  @Override
  public Collection<V> removeAll(@Nullable Object key) {