* {@link #hashCode} and {@link #equals}.
 */
public abstract class AbstractAttributeContainer implements AttributeContainerInternal {

    @Override
    public Map<Attribute<?>, ?> asMap() {
        return asImmutable().asMap();
    }

    @Override
    public boolean isEmpty() {
        return keySet().isEmpty();
    }

    @Override
    public boolean contains(Attribute<?> key) {

      Collection<V> collection = multimap().asMap().get(key);
      if (collection != null) {
        multimap().clear();
        assertEmpty(collection);
      }
    }
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testClearPropagatesToAsMap() {
    Map<K, Collection<V>> asMap = multimap().asMap();
    multimap().clear();
    assertEmpty(asMap);
  }

  @MapFeature.Require(SUPPORTS_REMOVE)

   *
   * <p>When passed a key that is present in the map, {@code asMap().get(Object)} has the same
   * behavior as {@link #get}, returning a live collection. When passed a key that is not present,
   * however, {@code asMap().get(Object)} returns {@code null} instead of an empty collection.
   *

   * just back this out once we stop doing that (which we'll do after our internal GWT setup
   * changes).
   */
  @Override
  public ImmutableMap<Object, Collection<Object>> asMap() {
    return super.asMap();
  }

  private Object readResolve() {
    return INSTANCE; // preserve singleton property
  }

  private static final long serialVersionUID = 0;

    for (Collection<V> valueCollection : multimap().asMap().values()) {
      SortedSet<V> valueSet = (SortedSet<V>) valueCollection;
      assertEquals(multimap().valueComparator(), valueSet.comparator());
    }
  }

  public void testAsMapGetImplementsSortedSet() {
    for (K key : multimap().keySet()) {
      SortedSet<V> valueSet = (SortedSet<V>) multimap().asMap().get(key);

   *
   * <p>When passed a key that is present in the map, {@code asMap().get(Object)} has the same
   * behavior as {@link #get}, returning a live collection. When passed a key that is not present,
   * however, {@code asMap().get(Object)} returns {@code null} instead of an empty collection.
   *

   *
   * <p>When passed a key that is present in the map, {@code asMap().get(Object)} has the same
   * behavior as {@link #get}, returning a live collection. When passed a key that is not present,
   * however, {@code asMap().get(Object)} returns {@code null} instead of an empty collection.
   *

   * this map with the more specific generic type {@code Map<K, List<V>>}, call {@link
   * Multimaps#asMap(ListMultimap)} instead.
   */
  @Override
  Map<K, Collection<V>> asMap();

  /**
   * Compares the specified object to this multimap for equality.
   *
   * <p>Two {@code ListMultimap} instances are equal if, for each key, they contain the same values

   * this map with the more specific generic type {@code Map<K, List<V>>}, call {@link
   * Multimaps#asMap(ListMultimap)} instead.
   */
  @Override
  Map<K, Collection<V>> asMap();

  /**
   * Compares the specified object to this multimap for equality.
   *
   * <p>Two {@code ListMultimap} instances are equal if, for each key, they contain the same values

    assertEqualInOrder(values, multimap().get(key));

    if (!values.isEmpty()) {
      assertEqualInOrder(values, multimap().asMap().get(key));
      assertFalse(multimap().isEmpty());
    } else {
      assertNull(multimap().asMap().get(key));
    }

    assertEquals(values.size(), multimap().get(key).size());
    assertEquals(values.size() > 0, multimap().containsKey(key));