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(
      @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

   * 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

      return multiset().comparator();
    }

    @Override
    public SortedSet<E> subSet(@ParametricNullness E fromElement, @ParametricNullness E toElement) {
      return multiset().subMultiset(fromElement, CLOSED, toElement, OPEN).elementSet();
    }

    @Override
    public SortedSet<E> headSet(@ParametricNullness E toElement) {
      return multiset().headMultiset(toElement, OPEN).elementSet();
    }

      result = Multisets.immutableEntry(result.getElement(), result.getCount());
      entryIterator.remove();
      return result;
    }
    return null;
  }

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

      result = Multisets.immutableEntry(result.getElement(), result.getCount());
      entryIterator.remove();
      return result;
    }
    return null;
  }

  @Override
  public SortedMultiset<E> subMultiset(
      @ParametricNullness E fromElement,
      BoundType fromBoundType,
      @ParametricNullness E toElement,
      BoundType toBoundType) {

   * works better than Ordering.natural().nullsFirst() because, if null comes before all other
   * values, it lies outside the submap/submultiset ranges we test, and the variety of tests that
   * exercise null handling fail on those subcollections.
   */
  public abstract static class NullsBefore implements Comparator<@Nullable String>, Serializable {