implements Multiset<E> {
  // Query Operations

  @Override
  public boolean isEmpty() {
    return entrySet().isEmpty();
  }

  @Override
  public boolean contains(@CheckForNull Object element) {
    return count(element) > 0;
  }

  // Modification Operations
  @CanIgnoreReturnValue
  @Override
  public final boolean add(@ParametricNullness E element) {

    implements Multiset<E> {
  // Query Operations

  @Override
  public boolean isEmpty() {
    return entrySet().isEmpty();
  }

  @Override
  public boolean contains(@CheckForNull Object element) {
    return count(element) > 0;
  }

  // Modification Operations
  @CanIgnoreReturnValue
  @Override
  public final boolean add(@ParametricNullness E element) {