*
   * @since 7.0 (this version overrides the {@code ForwardingCollection} version as of 12.0)
   */
  @Override
  protected boolean standardRemoveAll(Collection<?> collection) {
    return Sets.removeAllImpl(this, checkNotNull(collection)); // for GWT
  }

  /**
   * A sensible definition of {@link #equals} in terms of {@link #size} and {@link #containsAll}. If

    return Multisets.addAllImpl(this, elementsToAdd);
  }

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

  @CanIgnoreReturnValue
  @Override
  public final boolean retainAll(Collection<?> elementsToRetain) {
    return Multisets.retainAllImpl(this, elementsToRetain);
  }