* Multiset}.
   */
  @CanIgnoreReturnValue
  @Override
  public final boolean addAll(Collection<? extends E> elementsToAdd) {
    return Multisets.addAllImpl(this, elementsToAdd);
  }

  @CanIgnoreReturnValue
  @Override
  public final boolean removeAll(Collection<?> elementsToRemove) {
    return Multisets.removeAllImpl(this, elementsToRemove);
  }

   * Multiset}.
   */
  @CanIgnoreReturnValue
  @Override
  public final boolean addAll(Collection<? extends E> elementsToAdd) {
    return Multisets.addAllImpl(this, elementsToAdd);
  }

  @CanIgnoreReturnValue
  @Override
  public final boolean removeAll(Collection<?> elementsToRemove) {
    return Multisets.removeAllImpl(this, elementsToRemove);
  }

   * wish to override {@link #addAll(int, Collection)} to forward to this implementation.
   *
   * @since 7.0
   */
  protected boolean standardAddAll(int index, Iterable<? extends E> elements) {
    return Lists.addAllImpl(this, index, elements);
  }

  /**
   * A sensible default implementation of {@link #indexOf}, in terms of {@link #listIterator()}. If

   * wish to override {@link #addAll(int, Collection)} to forward to this implementation.
   *
   * @since 7.0
   */
  protected boolean standardAddAll(int index, Iterable<? extends E> elements) {
    return Lists.addAllImpl(this, index, elements);
  }

  /**
   * A sensible default implementation of {@link #indexOf}, in terms of {@link #listIterator()}. If