return Maps.safeContainsKey(columnMap(), columnKey);
  }

  @Override
  public Set<R> rowKeySet() {
    return rowMap().keySet();
  }

  @Override
  public Set<C> columnKeySet() {
    return columnMap().keySet();
  }

  @Override
  public boolean containsValue(@Nullable Object value) {
    for (Map<C, V> row : rowMap().values()) {
      if (row.containsValue(value)) {

  public void testSameComparator() {
    assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Sets.newTreeSet()));
    assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Maps.newTreeMap().keySet()));
    assertTrue(
        SortedIterables.hasSameComparator(
            Ordering.natural().reverse(), Sets.newTreeSet(Ordering.natural().reverse())));
  }

  public void testComparator() {

     *
     * @param cmdList the command list to add properties to
     */
    protected void addFessConfigProperties(final List<String> cmdList) {
        System.getProperties()
                .keySet()
                .stream()
                .filter(k -> k != null && k.toString().startsWith(Constants.FESS_CONFIG_PREFIX))
                .forEach(k -> addSystemProperty(cmdList, k.toString(), null, null));
    }

        Set<?> set = (Set<?>) obj;
        return inputSet.keySet().containsAll(set);
      }
      return false;
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      if (obj instanceof PowerSet) {
        PowerSet<?> that = (PowerSet<?>) obj;
        return inputSet.keySet().equals(that.inputSet.keySet());
      }
      return super.equals(obj);
    }

    assertThrows(UnsupportedOperationException.class, () -> map.tailMap("a").keySet().add("a"));
    assertThrows(UnsupportedOperationException.class, () -> map.headMap("r").keySet().add("a"));
    assertThrows(
        UnsupportedOperationException.class, () -> map.headMap("r").tailMap("m").keySet().add("a"));
  }

  public void testAsMapSortedEmpty() {

    }

    /**
     * Returns a Set view of the keys contained in this map.
     *
     * @return a set view of the keys contained in this map
     */
    @Override
    public Set<String> keySet() {
        return parent.keySet();
    }

    /**
     * Returns a Collection view of the values contained in this map.
     *
     * @return a collection view of the values contained in this map
     */
    @Override

      Set<K> keySet = new HashSet<>();
      List<Entry<K, V>> builder = new ArrayList<>();
      for (Object o : elements) {
        Entry<?, ?> entry = (Entry<?, ?>) o;
        // These come from Entry<K, Collection<V>>> objects somewhere.
        @SuppressWarnings("unchecked")
        K key = (K) entry.getKey();
        keySet.add(key);

  @CollectionSize.Require(SEVERAL)
  public void testClearConcurrentWithKeySetIteration() {
    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<K> iterator = getMap().keySet().iterator();
          getMap().clear();
          iterator.next();
        });
  }

  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
  @CollectionSize.Require(SEVERAL)

    multimapView.remove("bar", 2);
    assertFalse(multimapView.containsKey("bar"));
    assertFalse(map.containsKey("bar"));
    assertEquals(map.keySet(), multimapView.keySet());
    assertEquals(map.keySet(), multimapView.keys().elementSet());
    assertThat(multimapView.keys()).contains("foo");
    assertThat(multimapView.values()).contains(1);

        if (acceptedApiChanges != null) {
            this.acceptedApiChanges = AcceptedApiChanges.fromAcceptedChangesMap(acceptedApiChanges.get()).keySet();
        } else {
            this.acceptedApiChanges = Collections.emptySet();
        }
    }

    @Override
    @SuppressWarnings("unchecked")
    public void execute(ViolationCheckContext context) {