multimap.put("a", 11);
    multimap.put("b", 2);
    multimap.put("c", 3);
    multimap.put("d", 4);
    multimap.put("e", 5);
    multimap.put("e", 55);

    multimap.keySet().tailSet("d").clear();
    assertEquals(ImmutableSet.of("a", "b", "c"), multimap.keySet());
    assertEquals(4, multimap.size());
    assertEquals(4, multimap.values().size());
    assertEquals(4, multimap.keys().size());
  }

  }

  public void testRowKeySetTailSet() {
    sortedTable = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    Set<String> set = sortedTable.rowKeySet().tailSet("cat");
    assertEquals(singleton("foo"), set);
    set.clear();
    assertTrue(set.isEmpty());
    assertEquals(singleton("bar"), sortedTable.rowKeySet());
  }

  public void testRowKeySetSubSet() {

    multimap.put("a", 11);
    multimap.put("b", 2);
    multimap.put("c", 3);
    multimap.put("d", 4);
    multimap.put("e", 5);
    multimap.put("e", 55);

    multimap.keySet().tailSet("d").clear();
    assertEquals(ImmutableSet.of("a", "b", "c"), multimap.keySet());
    assertEquals(4, multimap.size());
    assertEquals(4, multimap.values().size());
    assertEquals(4, multimap.keys().size());
  }

    return sortedDelegate.firstKey();
  }

  @Override
  public @Nullable K lastKey() {
    return sortedDelegate.lastKey();
  }

  @Nullable K higher(K k) {
    Iterator<K> iterator = keySet().tailSet(k).iterator();
    while (iterator.hasNext()) {
      K tmp = iterator.next();
      if (comparator().compare(k, tmp) < 0) {
        return tmp;
      }
    }
    return null;
  }

  @Override

    ImmutableSortedSet<Integer> asSet = RANGE_SET_ONE.asSet(DiscreteDomain.integers());

    for (int i = 0; i <= 20; i++) {
      assertEquals(asSet.tailSet(i, false), expectedSet.tailSet(i, false));
      assertEquals(asSet.tailSet(i, true), expectedSet.tailSet(i, true));
    }
  }

  public void testAsSetSubSet() {
    ImmutableSortedSet<Integer> expectedSet = ImmutableSortedSet.of(2, 3, 4, 8, 9, 16, 17);

  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return forward.descendingIterator();
  }

  @Override
  ImmutableSortedSet<E> headSetImpl(E toElement, boolean inclusive) {
    return forward.tailSet(toElement, inclusive).descendingSet();
  }

  @Override
  ImmutableSortedSet<E> subSetImpl(
      E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) {

  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return forward.descendingIterator();
  }

  @Override
  ImmutableSortedSet<E> headSetImpl(E toElement, boolean inclusive) {
    return forward.tailSet(toElement, inclusive).descendingSet();
  }

  @Override
  ImmutableSortedSet<E> subSetImpl(
      E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) {

      if (from == Bound.NO_BOUND && to == Bound.INCLUSIVE) {
        return set.headSet(lastInclusive, true);
      } else if (from == Bound.EXCLUSIVE && to == Bound.NO_BOUND) {
        return set.tailSet(firstExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.EXCLUSIVE) {
        return set.subSet(firstExclusive, false, lastExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.INCLUSIVE) {

      if (from == Bound.NO_BOUND && to == Bound.INCLUSIVE) {
        return set.headSet(lastInclusive, true);
      } else if (from == Bound.EXCLUSIVE && to == Bound.NO_BOUND) {
        return set.tailSet(firstExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.EXCLUSIVE) {
        return set.subSet(firstExclusive, false, lastExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.INCLUSIVE) {

    assertEquals(StringLength.COMPARATOR, keySet.comparator());
    assertEquals(Sets.<@Nullable String>newHashSet(null, "tree"), keySet.headSet("yahoo"));
    assertEquals(newHashSet("google"), keySet.tailSet("yahoo"));
    assertEquals(newHashSet("tree"), keySet.subSet("ask", "yahoo"));
  }

  @GwtIncompatible // SerializableTester
  public void testExplicitComparatorSerialization() {