/**
   * A sensible definition of {@link #lowerEntry} in terms of the {@code lastEntry()} of {@link
   * #headMap(Object, boolean)}. If you override {@code headMap}, you may wish to override {@code
   * lowerEntry} to forward to this implementation.
   */
  protected @Nullable Entry<K, V> standardLowerEntry(@ParametricNullness K key) {
    return headMap(key, false).lastEntry();
  }

  @Override

  /**
   * A sensible definition of {@link #lowerEntry} in terms of the {@code lastEntry()} of {@link
   * #headMap(Object, boolean)}. If you override {@code headMap}, you may wish to override {@code
   * lowerEntry} to forward to this implementation.
   */
  protected @Nullable Entry<K, V> standardLowerEntry(@ParametricNullness K key) {
    return headMap(key, false).lastEntry();
  }

  @Override

      extends AbstractNavigableMap<Cut<C>, Range<C>> {
    private final NavigableMap<Cut<C>, Range<C>> rangesByLowerBound;

    /**
     * upperBoundWindow represents the headMap/subMap/tailMap view of the entire "ranges by upper
     * bound" map; it's a constraint on the *keys*, and does not affect the values.
     */
    private final Range<Cut<C>> upperBoundWindow;

        return tmp;
      }
    }
    return null;
  }

  @Override
  public ImmutableSortedMap<K, V> headMap(K toKey) {
    checkNotNull(toKey);
    return newView(sortedDelegate.headMap(toKey));
  }

  ImmutableSortedMap<K, V> headMap(K toKey, boolean inclusive) {
    checkNotNull(toKey);
    if (inclusive) {
      K tmp = higher(toKey);
      if (tmp == null) {

    }

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

    @Override
    public NavigableMap<K, Collection<V>> headMap(@ParametricNullness K toKey, boolean inclusive) {
      return new NavigableAsMap(sortedMap().headMap(toKey, inclusive));
    }

    @Override

      checkArgument(rangeContains(checkNotNull(fromKey)) && rangeContains(checkNotNull(toKey)));
      return new TreeRow(rowKey, fromKey, toKey);
    }

    @Override
    public SortedMap<C, V> headMap(C toKey) {
      checkArgument(rangeContains(checkNotNull(toKey)));
      return new TreeRow(rowKey, lowerBound, toKey);
    }

    @Override
    public SortedMap<C, V> tailMap(C fromKey) {

      checkArgument(rangeContains(checkNotNull(fromKey)) && rangeContains(checkNotNull(toKey)));
      return new TreeRow(rowKey, fromKey, toKey);
    }

    @Override
    public SortedMap<C, V> headMap(C toKey) {
      checkArgument(rangeContains(checkNotNull(toKey)));
      return new TreeRow(rowKey, lowerBound, toKey);
    }

    @Override
    public SortedMap<C, V> tailMap(C fromKey) {

        ImmutableSortedMap.of("one", 1, "two", 2, "three", 3).headMap("three", true);
    assertThat(map.entrySet())
        .containsExactly(immutableEntry("one", 1), immutableEntry("three", 3))
        .inOrder();
  }

  public void testHeadMapExclusive() {
    Map<String, Integer> map =
        ImmutableSortedMap.of("one", 1, "two", 2, "three", 3).headMap("three", false);

          if (subRange.isEmpty()) {
            return emptyIterator();
          }
          Iterator<RangeMapEntry<K, V>> backingItr =
              entriesByLowerBound
                  .headMap(subRange.upperBound, false)
                  .descendingMap()
                  .values()
                  .iterator();
          return new AbstractIterator<Entry<Range<K>, V>>() {

            @Override

  }

  public void testRowKeyMapHeadMap() {
    sortedTable = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    Map<String, Map<Integer, Character>> map = sortedTable.rowMap().headMap("cat");
    assertEquals(1, map.size());
    assertEquals(ImmutableMap.of(1, 'b'), map.get("bar"));
    map.clear();
    assertTrue(map.isEmpty());
    assertEquals(singleton("foo"), sortedTable.rowKeySet());
  }