public SortedMultiset<E> subMultiset(
      @ParametricNullness E fromElement,
      BoundType fromBoundType,
      @ParametricNullness E toElement,
      BoundType toBoundType) {
    // These are checked elsewhere, but NullPointerTester wants them checked eagerly.
    checkNotNull(fromBoundType);
    checkNotNull(toBoundType);
    return tailMultiset(fromElement, fromBoundType).headMultiset(toElement, toBoundType);
  }

    }

    @Override
    public NavigableSet<E> tailSet(@ParametricNullness E fromElement, boolean inclusive) {
      return forward.headSet(fromElement, inclusive).descendingSet();
    }

    @Override
    public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
      return standardTailSet(fromElement);
    }

    @SuppressWarnings("unchecked")
    @Override