testEmptyRangeSubMultiset(
        sortedMultiset.subMultiset(a.getElement(), CLOSED, a.getElement(), OPEN));
    testEmptyRangeSubMultiset(
        sortedMultiset.subMultiset(a.getElement(), OPEN, a.getElement(), OPEN));
    testEmptyRangeSubMultiset(
        sortedMultiset.subMultiset(a.getElement(), OPEN, a.getElement(), CLOSED));
    testEmptyRangeSubMultiset(
        sortedMultiset.subMultiset(b.getElement(), CLOSED, a.getElement(), CLOSED));

    testEmptyRangeSubMultiset(
        sortedMultiset.subMultiset(a.getElement(), CLOSED, a.getElement(), OPEN));
    testEmptyRangeSubMultiset(
        sortedMultiset.subMultiset(a.getElement(), OPEN, a.getElement(), OPEN));
    testEmptyRangeSubMultiset(
        sortedMultiset.subMultiset(a.getElement(), OPEN, a.getElement(), CLOSED));
    testEmptyRangeSubMultiset(
        sortedMultiset.subMultiset(b.getElement(), CLOSED, a.getElement(), CLOSED));

  }

  @Override
  public SortedMultiset<E> subMultiset(
      @ParametricNullness E lowerBound,
      BoundType lowerBoundType,
      @ParametricNullness E upperBound,
      BoundType upperBoundType) {
    return delegate().subMultiset(lowerBound, lowerBoundType, upperBound, upperBoundType);
  }

  /**
   * A sensible definition of {@link #subMultiset(Object, BoundType, Object, BoundType)} in terms of

    Multiset<String> subMultiset = HashMultiset.create();
    assertTrue(Multisets.containsOccurrences(superMultiset, subMultiset));
    assertFalse(Multisets.containsOccurrences(subMultiset, superMultiset));
  }

  public void testContainsOccurrences() {
    Multiset<String> superMultiset = HashMultiset.create(asList("a", "b", "a"));
    Multiset<String> subMultiset = HashMultiset.create(asList("a", "b"));

  }

  @Override
  public SortedMultiset<E> subMultiset(
      @ParametricNullness E lowerBound,
      BoundType lowerBoundType,
      @ParametricNullness E upperBound,
      BoundType upperBoundType) {
    return delegate().subMultiset(lowerBound, lowerBoundType, upperBound, upperBoundType);
  }

  /**
   * A sensible definition of {@link #subMultiset(Object, BoundType, Object, BoundType)} in terms of

  }

  @Override
  public SortedMultiset<E> subMultiset(
      E lowerBound, BoundType lowerBoundType, E upperBound, BoundType upperBoundType) {
    return delegate().subMultiset(lowerBound, lowerBoundType, upperBound, upperBoundType);
  }

  /**
   * A sensible definition of {@link #subMultiset(Object, BoundType, Object, BoundType)} in terms of

  }

  @Override
  public SortedMultiset<E> subMultiset(
      E lowerBound, BoundType lowerBoundType, E upperBound, BoundType upperBoundType) {
    return Multisets.unmodifiableSortedMultiset(
        delegate().subMultiset(lowerBound, lowerBoundType, upperBound, upperBoundType));
  }

  @Override

   * created for them.
   */
  enum NoRecurse implements Feature<Void> {
    SUBMULTISET,
    DESCENDING;

    @Override
    public Set<Feature<? super Void>> getImpliedFeatures() {
      return emptySet();
    }
  }

  /** Two bounds (from and to) define how to build a subMultiset. */
  enum Bound {
    INCLUSIVE,
    EXCLUSIVE,
    NO_BOUND;
  }

  }

  @Override
  public SortedMultiset<E> subMultiset(
      @ParametricNullness E lowerBound,
      BoundType lowerBoundType,
      @ParametricNullness E upperBound,
      BoundType upperBoundType) {
    return Multisets.unmodifiableSortedMultiset(
        delegate().subMultiset(lowerBound, lowerBoundType, upperBound, upperBoundType));
  }

  @Override

    return forwardMultiset().tailMultiset(toElement, boundType).descendingMultiset();
  }

  @Override
  public SortedMultiset<E> subMultiset(
      E fromElement, BoundType fromBoundType, E toElement, BoundType toBoundType) {
    return forwardMultiset()
        .subMultiset(toElement, toBoundType, fromElement, fromBoundType)
        .descendingMultiset();
  }

  @Override