}

  @Override
  @CheckForNull
  public Entry<E> pollLastEntry() {
    return forwardMultiset().pollFirstEntry();
  }

  @Override
  public SortedMultiset<E> headMultiset(E toElement, BoundType boundType) {
    return forwardMultiset().tailMultiset(toElement, boundType).descendingMultiset();
  }

  @Override
  public SortedMultiset<E> subMultiset(

  }

  @Override
  @CheckForNull
  public Entry<E> pollLastEntry() {
    return forwardMultiset().pollFirstEntry();
  }

  @Override
  public SortedMultiset<E> headMultiset(@ParametricNullness E toElement, BoundType boundType) {
    return forwardMultiset().tailMultiset(toElement, boundType).descendingMultiset();
  }

  @Override
  public SortedMultiset<E> subMultiset(

    assertEquals(Integer.MAX_VALUE, ms.count("b"));
    assertEquals(3, ms.count("c"));

    assertEquals(Integer.MAX_VALUE, ms.headMultiset("c", CLOSED).size());
    assertEquals(Integer.MAX_VALUE, ms.headMultiset("b", CLOSED).size());
    assertEquals(Integer.MAX_VALUE, ms.headMultiset("a", CLOSED).size());

    assertEquals(3, ms.tailMultiset("c", CLOSED).size());

                }

                if (to == Bound.INCLUSIVE) {
                  multiset = multiset.headMultiset(lastInclusive, BoundType.CLOSED);
                } else if (to == Bound.EXCLUSIVE) {
                  multiset = multiset.headMultiset(lastExclusive, BoundType.OPEN);
                }

                return multiset;
              }
            })

    return Ints.saturatedCast(size);
  }

  @Override
  public ImmutableSortedSet<E> elementSet() {
    return elementSet;
  }

  @Override
  public ImmutableSortedMultiset<E> headMultiset(E upperBound, BoundType boundType) {
    return getSubMultiset(0, elementSet.headIndex(upperBound, checkNotNull(boundType) == CLOSED));
  }

  @Override

  @CheckForNull
  public final Entry<E> pollLastEntry() {
    throw new UnsupportedOperationException();
  }

  @Override
  public abstract ImmutableSortedMultiset<E> headMultiset(E upperBound, BoundType boundType);

  @Override
  public ImmutableSortedMultiset<E> subMultiset(
      E lowerBound, BoundType lowerBoundType, E upperBound, BoundType upperBoundType) {
    checkArgument(

        prevEntry = null;
      }
    };
  }

  @Override
  public Iterator<E> iterator() {
    return Multisets.iteratorImpl(this);
  }

  @Override
  public SortedMultiset<E> headMultiset(@ParametricNullness E upperBound, BoundType boundType) {
    return new TreeMultiset<>(
        rootReference,
        range.intersect(GeneralRange.upTo(comparator(), upperBound, boundType)),
        header);
  }

    }
  }

  @Override
  public Iterator<E> iterator() {
    return Multisets.iteratorImpl(this);
  }

  @Override
  public SortedMultiset<E> headMultiset(@ParametricNullness E upperBound, BoundType boundType) {
    return new TreeMultiset<>(
        rootReference,
        range.intersect(GeneralRange.upTo(comparator(), upperBound, boundType)),
        header);
  }