boolean fromInclusive,
        @ParametricNullness V toElement,
        boolean toInclusive) {
      return wrap(
          getSortedSetDelegate().subSet(fromElement, fromInclusive, toElement, toInclusive));
    }

    @Override
    public NavigableSet<V> headSet(@ParametricNullness V toElement, boolean inclusive) {
      return wrap(getSortedSetDelegate().headSet(toElement, inclusive));
    }

    @Override

  }

  @Override
  public SortedMultiset<E> headMultiset(E toElement, BoundType boundType) {
    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)

  }

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

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

  }

  @Override
  ImmutableSortedSet<E> headSetImpl(E toElement, boolean inclusive) {
    return getSubSet(0, headIndex(toElement, inclusive));
  }

  int headIndex(E toElement, boolean inclusive) {
    int index = Collections.binarySearch(elements, checkNotNull(toElement), comparator());
    if (index >= 0) {
      return inclusive ? index + 1 : index;
    } else {

  }

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

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

      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);
  }

  abstract Iterator<Entry<E>> descendingEntryIterator();

      return new FilteredSortedSet<>(
          ((SortedSet<E>) unfiltered).subSet(fromElement, toElement), predicate);
    }

    @Override
    public SortedSet<E> headSet(@ParametricNullness E toElement) {
      return new FilteredSortedSet<>(((SortedSet<E>) unfiltered).headSet(toElement), predicate);
    }

    @Override

      @Override
      public SortedSet<E> headSet(@ParametricNullness E toElement) {
        return removeOnlySortedSet(super.headSet(toElement));
      }

      @Override
      public SortedSet<E> subSet(
          @ParametricNullness E fromElement, @ParametricNullness E toElement) {
        return removeOnlySortedSet(super.subSet(fromElement, toElement));
      }

      @Override

      @Override
      public SortedSet<E> headSet(@ParametricNullness E toElement) {
        return removeOnlySortedSet(super.headSet(toElement));
      }

      @Override
      public SortedSet<E> subSet(
          @ParametricNullness E fromElement, @ParametricNullness E toElement) {
        return removeOnlySortedSet(super.subSet(fromElement, toElement));
      }

      @Override

    @Override
    ImmutableSortedSet<C> headSetImpl(C toElement, boolean inclusive) {
      return subSet(Range.upTo(toElement, BoundType.forBoolean(inclusive)));
    }

    @Override
    ImmutableSortedSet<C> subSetImpl(
        C fromElement, boolean fromInclusive, C toElement, boolean toInclusive) {
      if (!fromInclusive && !toInclusive && Range.compareOrThrow(fromElement, toElement) == 0) {
        return ImmutableSortedSet.of();