*
   * @param element the element to count occurrences of
   * @return the number of occurrences of the element in this multiset; possibly zero but never
   *     negative
   */
  int count(@CompatibleWith("E") @Nullable Object element);

  // Bulk Operations

  /**
   * Adds a number of occurrences of an element to this multiset. Note that if {@code occurrences ==

   *
   * @param element the element to count occurrences of
   * @return the number of occurrences of the element in this multiset; possibly zero but never
   *     negative
   */
  int count(@CompatibleWith("E") @Nullable Object element);

  // Bulk Operations

  /**
   * Adds a number of occurrences of an element to this multiset. Note that if {@code occurrences ==

  @Override
  public int add(E element, int occurrences) {
    checkIsE(element);
    checkNonnegative(occurrences, "occurrences");
    if (occurrences == 0) {
      return count(element);
    }
    int index = element.ordinal();
    int oldCount = counts[index];
    long newCount = (long) oldCount + occurrences;
    checkArgument(newCount <= Integer.MAX_VALUE, "too many occurrences: %s", newCount);

    }

    @Override
    public int add(E element, int occurrences) {
      checkArgument(occurrences >= 0);
      Integer frequency = backingMap.getOrDefault(element, 0);
      if (occurrences == 0) {
        return frequency;
      }
      checkArgument(occurrences <= Integer.MAX_VALUE - frequency);
      backingMap.put(element, frequency + occurrences);
      return frequency;
    }

    @Override

     * @throws IllegalArgumentException if {@code occurrences} is negative, or if this operation
     *     would result in more than {@link Integer#MAX_VALUE} occurrences of the element
     */
    @CanIgnoreReturnValue
    public Builder<E> addCopies(E element, int occurrences) {
      contents.add(checkNotNull(element), occurrences);
      return this;
    }

    /**

    Keys() {
      super(FilteredEntryMultimap.this);
    }

    @Override
    public int remove(@Nullable Object key, int occurrences) {
      checkNonnegative(occurrences, "occurrences");
      if (occurrences == 0) {
        return count(key);
      }
      Collection<V> collection = unfiltered.asMap().get(key);
      if (collection == null) {
        return 0;
      }

  }

  @CanIgnoreReturnValue
  @Override
  public int add(@ParametricNullness E element, int occurrences) {
    return delegate().add(element, occurrences);
  }

  @CanIgnoreReturnValue
  @Override
  public int remove(@Nullable Object element, int occurrences) {
    return delegate().remove(element, occurrences);
  }

  @Override
  public Set<E> elementSet() {
    return delegate().elementSet();
  }

    Keys() {
      super(FilteredEntryMultimap.this);
    }

    @Override
    public int remove(@Nullable Object key, int occurrences) {
      checkNonnegative(occurrences, "occurrences");
      if (occurrences == 0) {
        return count(key);
      }
      Collection<V> collection = unfiltered.asMap().get(key);
      if (collection == null) {
        return 0;
      }

     * @throws IllegalArgumentException if {@code occurrences} is negative, or if this operation
     *     would result in more than {@link Integer#MAX_VALUE} occurrences of the element
     */
    @CanIgnoreReturnValue
    @Override
    public Builder<E> addCopies(E element, int occurrences) {
      super.addCopies(element, occurrences);
      return this;
    }

    /**

      return 0;
    }
  }

  @CanIgnoreReturnValue
  @Override
  public int add(@ParametricNullness E element, int occurrences) {
    checkNonnegative(occurrences, "occurrences");
    if (occurrences == 0) {
      return count(element);
    }
    checkArgument(range.contains(element));
    AvlNode<E> root = rootReference.get();
    if (root == null) {