Entry<K, V> secondEntry = iterator.next();
    K key = secondEntry.getKey();
    SortedMap<K, V> subMap = map.tailMap(key);
    subMap.remove(key);
    assertNull(subMap.remove(firstEntry.getKey()));
    assertEquals(map.size(), oldSize - 1);
    assertFalse(map.containsKey(key));
    assertEquals(subMap.size(), oldSize - 2);
  }

  public void testTailMapClearThrough() {
    SortedMap<K, V> map;
    try {

	ipToInsert := ip.Unmap()

	// We have already Unmap'd, so we can do a simple IsV6 y/n check now
	if ipToInsert.Is6() {
		return m.Deps.addIP(m.V6Name, ipToInsert, ipProto, comment, replace)
	}
	return m.Deps.addIP(m.V4Name, ipToInsert, ipProto, comment, replace)
}

func (m *IPSet) DeleteIP(ip netip.Addr, ipProto uint8) error {
	ipToDel := ip.Unmap()

   * This method returns a {@code ImmutableSortedMap}, consisting of the entries whose keys ranges
   * from {@code fromKey}, inclusive, to {@code toKey}, exclusive.
   *
   * <p>The {@link SortedMap#subMap} documentation states that a submap of a submap throws an {@link
   * IllegalArgumentException} if passed a {@code fromKey} less than an earlier {@code fromKey}.
   * However, this method doesn't throw an exception in that situation, but instead keeps the

    SortedMap<String, Integer> subMap = map.subMap("a", "b");
    assertTrue(subMap instanceof SynchronizedSortedMap);
    assertSame(mutex, ((SynchronizedSortedMap<String, Integer>) subMap).mutex);
  }

  public void testSubMap_k_b_k_b() {
    NavigableMap<String, Integer> map = create();
    NavigableMap<String, Integer> subMap = map.subMap("a", true, "b", false);
    assertTrue(subMap instanceof SynchronizedNavigableMap);

    List<Feature<?>> features = new ArrayList<>();
    features.add(NoRecurse.SUBMAP);
    features.addAll(parentBuilder.getFeatures());

    return newBuilderUsing(delegate, to, from)
        .named(parentBuilder.getName() + " subMap " + from + "-" + to)
        .withFeatures(features)
        .suppressing(parentBuilder.getSuppressedTests())

    return Maps.keyOrNull(higherEntry(key));
  }

  abstract Iterator<Entry<K, V>> descendingEntryIterator();

  @Override
  public SortedMap<K, V> subMap(@ParametricNullness K fromKey, @ParametricNullness K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  @Override
  public SortedMap<K, V> headMap(@ParametricNullness K toKey) {
    return headMap(toKey, false);
  }

  @Override

    List<Feature<?>> features = new ArrayList<>();
    features.add(NoRecurse.SUBMAP);
    features.addAll(parentBuilder.getFeatures());

    return newBuilderUsing(delegate, to, from)
        .named(parentBuilder.getName() + " subMap " + from + "-" + to)
        .withFeatures(features)
        .suppressing(parentBuilder.getSuppressedTests())

      } else if (from == Bound.EXCLUSIVE && to == Bound.EXCLUSIVE) {
        return map.subMap(firstExclusive, false, lastExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.INCLUSIVE) {
        return map.subMap(firstExclusive, false, lastInclusive, true);
      } else if (from == Bound.INCLUSIVE && to == Bound.INCLUSIVE) {
        return map.subMap(firstInclusive, true, lastInclusive, true);
      } else {

  }

  @Override
  @ParametricNullness
  public K lastKey() {
    return delegate().lastKey();
  }

  @Override
  public SortedMap<K, V> subMap(@ParametricNullness K fromKey, @ParametricNullness K toKey) {
    return delegate().subMap(fromKey, toKey);
  }

  @Override
  public SortedMap<K, V> tailMap(@ParametricNullness K fromKey) {
    return delegate().tailMap(fromKey);
  }

  /**

    return createMultimap().asMap().subMap("e", "p");
  }

  @Override
  protected Map<String, Collection<Integer>> makePopulatedMap() {
    TreeMultimap<String, Integer> multimap = createMultimap();
    multimap.put("f", 1);
    multimap.put("f", 2);
    multimap.put("g", 3);
    multimap.put("h", 4);
    return multimap.asMap().subMap("e", "p");
  }

  @Override