public boolean isEmpty() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.isEmpty();
    }

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

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

    @Override

    assertThat(segment.containsValue(value)).isTrue();
    assertThat(segment.containsValue(dummyValue)).isTrue();

    // expired
    dummy.setAccessTime(ticker.read() - 2);
    assertThat(segment.get(key, hash)).isNull();
    assertThat(segment.containsKey(key, hash)).isFalse();
    assertThat(segment.containsValue(value)).isTrue();
    assertThat(segment.containsValue(dummyValue)).isFalse();
  }

    assertThat(segment.containsValue(value)).isTrue();
    assertThat(segment.containsValue(dummyValue)).isTrue();

    // expired
    dummy.setAccessTime(ticker.read() - 2);
    assertThat(segment.get(key, hash)).isNull();
    assertThat(segment.containsKey(key, hash)).isFalse();
    assertThat(segment.containsValue(value)).isTrue();
    assertThat(segment.containsValue(dummyValue)).isFalse();
  }

    }
  }

  protected void expectMissingValues(V... elements) {
    for (V element : elements) {
      assertFalse("Should not contain value " + element, getMap().containsValue(element));
    }
  }

  /**
   * @return an array of the proper size with {@code null} as the key of the middle element.
   */
  protected Entry<K, V>[] createArrayWithNullKey() {

    cache.put(2456, 56);
    cache.put(2, 15);

    fakeTicker.advance(10001, MILLISECONDS);

    assertThat(cache.asMap().containsValue(15)).isTrue();
    assertThat(cache.asMap().containsValue(56)).isTrue();
    assertThat(cache.asMap().containsValue(2675)).isFalse();
  }

  // we are testing our implementation of Map.containsKey
  @SuppressWarnings("ContainsEntryAfterGetInteger")
  @Test

      return delegate.containsKey(checkValid(key));
    } catch (NullPointerException | ClassCastException e) {
      return false;
    }
  }

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

  @Override
  public NavigableSet<K> descendingKeySet() {
    return delegate.descendingKeySet();
  }

  @Override

   */
  ALLOWS_NULL_KEY_QUERIES,
  ALLOWS_NULL_KEYS(ALLOWS_NULL_KEY_QUERIES),
  /**
   * The map does not throw {@code NullPointerException} on calls such as {@code
   * containsValue(null)}, {@code values().contains(null)} or {@code values().remove(null)}.
   */
  ALLOWS_NULL_VALUE_QUERIES,
  ALLOWS_NULL_VALUES(ALLOWS_NULL_VALUE_QUERIES),
  /**

          "Inverse should not contain key " + reversed.getKey(),
          inv.containsKey(reversed.getKey()));
      assertFalse(
          "Inverse should not contain value " + reversed.getValue(),
          inv.containsValue(reversed.getValue()));
      /*
       * TODO(cpovirk): This is a bit stronger than super.expectMissing(), which permits a <key,
       * someOtherValue> pair.
       */
      assertNull(

    assertFalse(INSTANCE.containsColumn(1));
  }

  public void testContainsRow() {
    assertFalse(INSTANCE.containsRow('a'));
  }

  public void testContainsValue() {
    assertFalse(INSTANCE.containsValue("blah"));
  }

  public void testRow() {
    assertEquals(ImmutableMap.of(), INSTANCE.row('a'));
  }

  public void testRowKeySet() {
    assertEquals(ImmutableSet.of(), INSTANCE.rowKeySet());
  }

  }

  @Override
  public Iterator<V> iterator() {
    return Maps.valueIterator(multimap.entries().iterator());
  }

  @Override
  public boolean contains(@Nullable Object o) {
    return multimap.containsValue(o);
  }

  @Override
  public int size() {
    return multimap.size();
  }

  @Override
  public boolean remove(@Nullable Object o) {