@CheckForNull
  public K lowerKey(@ParametricNullness K key) {
    return Maps.keyOrNull(lowerEntry(key));
  }

  @Override
  @CheckForNull
  public K floorKey(@ParametricNullness K key) {
    return Maps.keyOrNull(floorEntry(key));
  }

  @Override
  @CheckForNull
  public K ceilingKey(@ParametricNullness K key) {
    return Maps.keyOrNull(ceilingEntry(key));
  }

  @Override
  @CheckForNull

  }

  /**
   * A sensible definition of {@link #putAll(Map)} in terms of {@link #put(Object, Object)}. If you
   * override {@link #put(Object, Object)}, you may wish to override {@link #putAll(Map)} to forward
   * to this implementation.
   *
   * @since 7.0
   */
  protected void standardPutAll(Map<? extends K, ? extends V> map) {
    Maps.putAllImpl(this, map);
  }

  /**

    assertFalse(entrySet.remove(Maps.immutableEntry(10, 'X')));
    assertTrue(entrySet.remove(Maps.immutableEntry(20, 'X')));
    assertFalse(entrySet.remove(Maps.immutableEntry(15, 'X')));
    entrySet = row.entrySet();
    assertTrue(entrySet.remove(Maps.immutableEntry(10, 'X')));
    assertFalse(entrySet.remove(Maps.immutableEntry(20, 'X')));
    assertFalse(entrySet.remove(Maps.immutableEntry(15, 'X')));
  }

    public SampleElements<Entry<Country, String>> samples() {
      return new SampleElements<>(
          Maps.immutableEntry(Country.CANADA, "DOLLAR"),
          Maps.immutableEntry(Country.CHILE, "PESO"),
          Maps.immutableEntry(Country.UK, "POUND"),
          Maps.immutableEntry(Country.JAPAN, "YEN"),
          Maps.immutableEntry(Country.SWITZERLAND, "FRANC"));
    }

    @SuppressWarnings("unchecked")
    @Override

    assertEquals(Maps.immutableEntry("foo", 5), entryIterator.next());
    assertEquals(Maps.immutableEntry("bar", 4), entryIterator.next());
    assertEquals(Maps.immutableEntry("foo", 3), entryIterator.next());
    assertEquals(Maps.immutableEntry("cow", 2), entryIterator.next());
    assertEquals(Maps.immutableEntry("bar", 1), entryIterator.next());

  SortedMap<String, Integer> createUnfiltered() {
    return Maps.newTreeMap();
  }

  public void testFirstAndLastKeyFilteredMap() {
    SortedMap<String, Integer> unfiltered = createUnfiltered();
    unfiltered.put("apple", 2);
    unfiltered.put("banana", 6);
    unfiltered.put("cat", 3);
    unfiltered.put("dog", 5);

    SortedMap<String, Integer> filtered = Maps.filterEntries(unfiltered, CORRECT_LENGTH);

    assertFalse(entrySet.remove(Maps.immutableEntry(10, 'X')));
    assertTrue(entrySet.remove(Maps.immutableEntry(20, 'X')));
    assertFalse(entrySet.remove(Maps.immutableEntry(15, 'X')));
    entrySet = row.entrySet();
    assertTrue(entrySet.remove(Maps.immutableEntry(10, 'X')));
    assertFalse(entrySet.remove(Maps.immutableEntry(20, 'X')));
    assertFalse(entrySet.remove(Maps.immutableEntry(15, 'X')));
  }

      ImmutableSet<R> rowSpace,
      ImmutableSet<C> columnSpace) {
    Map<R, Integer> rowIndex = Maps.indexMap(rowSpace);
    Map<R, Map<C, V>> rows = Maps.newLinkedHashMap();
    for (R row : rowSpace) {
      rows.put(row, new LinkedHashMap<C, V>());
    }
    Map<C, Map<R, V>> columns = Maps.newLinkedHashMap();
    for (C col : columnSpace) {
      columns.put(col, new LinkedHashMap<R, V>());
    }

            multimap.entryPredicate(), Maps.<V>valuePredicateOnEntries(Predicates.in(c))));
  }

  @Override
  public boolean retainAll(Collection<?> c) {
    return Iterables.removeIf(
        multimap.unfiltered().entries(),
        // explicit <Entry<K, V>> is required to build with JDK6
        Predicates.<Entry<K, V>>and(
            multimap.entryPredicate(),

    for (Map<C, V> row : rowMap().values()) {
      if (row.containsValue(value)) {
        return true;
      }
    }
    return false;
  }

  @Override
  public boolean contains(@CheckForNull Object rowKey, @CheckForNull Object columnKey) {
    Map<C, V> row = Maps.safeGet(rowMap(), rowKey);
    return row != null && Maps.safeContainsKey(row, columnKey);
  }

  @Override