*/
  Collection<V> get(@ParametricNullness K key);

  /**
   * Returns a view collection of all <i>distinct</i> keys contained in this multimap. Note that the
   * key set contains a key if and only if this multimap maps that key to at least one value.
   *
   * <p>Changes to the returned set will update the underlying multimap, and vice versa. However,

    boolean contained = false;
    if (actual instanceof Collection) {
      contained = ((Collection<?>) actual).contains(expected);
    } else {
      for (Object o : actual) {
        if (equal(o, expected)) {
          contained = true;
          break;
        }
      }
    }

    if (!contained) {
      fail("Not true that " + actual + " contains " + expected);

   * </ol>
   *
   * @param multimap the presumed-immutable multimap
   * @param sampleKey a key of the same type as that contained by {@code multimap}. {@code multimap}
   *     may or may not have {@code sampleKey} as a key.
   * @param sampleValue a key of the same type as that contained by {@code multimap}. {@code
   *     multimap} may or may not have {@code sampleValue} as a key.
   */

  }

  /**
   * Returns a comparator of {@link Optional} values which treats {@link Optional#empty} as less
   * than all other values, and orders the rest using {@code valueComparator} on the contained
   * value.
   *
   * @since 22.0 (but only since 33.4.0 in the Android flavor)
   */
  public static <T> Comparator<Optional<T>> emptiesFirst(Comparator<? super T> valueComparator) {

  /**
   * Determines whether this multiset contains the specified element.
   *
   * <p>This method refines {@link Collection#contains} to further specify that it <b>may not</b>
   * throw an exception in response to {@code element} being null or of the wrong type.
   *
   * @param element the element to check for
   * @return {@code true} if this multiset contains at least one occurrence of the element
   */
  @Override

  }

  // Graph copy methods

  /**
   * Returns the subgraph of {@code graph} induced by {@code nodes}. This subgraph is a new graph
   * that contains all of the nodes in {@code nodes}, and all of the {@link Graph#edges() edges}
   * from {@code graph} for which both nodes are contained by {@code nodes}.
   *
   * @throws IllegalArgumentException if any element in {@code nodes} is not a node in the graph
   */

  }

  // Graph copy methods

  /**
   * Returns the subgraph of {@code graph} induced by {@code nodes}. This subgraph is a new graph
   * that contains all of the nodes in {@code nodes}, and all of the {@link Graph#edges() edges}
   * from {@code graph} for which both nodes are contained by {@code nodes}.
   *
   * @throws IllegalArgumentException if any element in {@code nodes} is not a node in the graph
   */

  /**
   * Determines whether this multiset contains the specified element.
   *
   * <p>This method refines {@link Collection#contains} to further specify that it <b>may not</b>
   * throw an exception in response to {@code element} being null or of the wrong type.
   *
   * @param element the element to check for
   * @return {@code true} if this multiset contains at least one occurrence of the element
   */
  @Override

     */
    public boolean isEmpty() {
        return size == 0;
    }

    /**
     * Checks if an element is contained in the list.
     *
     * @param element the element
     * @return true if the element is contained in the list, false otherwise
     */
    public boolean contains(final E element) {
        return indexOf(element) != -1;
    }

    /**
     * Removes an element from the list.

    setHashTableMask(newMask);
    return newMask;
  }

  @Override
  public boolean contains(@Nullable Object object) {
    if (needsAllocArrays()) {
      return false;
    }
    Set<E> delegate = delegateOrNull();
    if (delegate != null) {
      return delegate.contains(object);
    }
    int hash = smearedHash(object);
    int mask = hashTableMask();