extends SynchronizedObject implements Multimap<K, V> {
    @CheckForNull transient Set<K> keySet;
    @CheckForNull transient Collection<V> valuesCollection;
    @CheckForNull transient Collection<Map.Entry<K, V>> entries;
    @CheckForNull transient Map<K, Collection<V>> asMap;
    @CheckForNull transient Multiset<K> keys;

    @SuppressWarnings("unchecked")
    @Override

      extends SynchronizedObject implements Multimap<K, V> {
    @CheckForNull transient Set<K> keySet;
    @CheckForNull transient Collection<V> valuesCollection;
    @CheckForNull transient Collection<Map.Entry<K, V>> entries;
    @CheckForNull transient Map<K, Collection<V>> asMap;
    @CheckForNull transient Multiset<K> keys;

    @SuppressWarnings("unchecked")
    @Override

  }

  private boolean containsMapping(
      @CheckForNull Object rowKey, @CheckForNull Object columnKey, @CheckForNull Object value) {
    return value != null && value.equals(get(rowKey, columnKey));
  }

  /** Remove a row key / column key / value mapping, if present. */
  private boolean removeMapping(
      @CheckForNull Object rowKey, @CheckForNull Object columnKey, @CheckForNull Object value) {

   * @since 20.0 (varargs overload since 2.0)
   */
  @CanIgnoreReturnValue
  public static <T> T checkNotNull(
      @CheckForNull T reference,
      String errorMessageTemplate,
      @CheckForNull Object p1,
      @CheckForNull Object p2,
      @CheckForNull Object p3,
      @CheckForNull Object p4) {
    if (reference == null) {
      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2, p3, p4));

    @ParametricNullness final K key;
    Collection<V> delegate;
    @CheckForNull final WrappedCollection ancestor;
    @CheckForNull final Collection<V> ancestorDelegate;

    WrappedCollection(
        @ParametricNullness K key,
        Collection<V> delegate,
        @CheckForNull WrappedCollection ancestor) {
      this.key = key;
      this.delegate = delegate;

  }

  private boolean containsMapping(
      @CheckForNull Object rowKey, @CheckForNull Object columnKey, @CheckForNull Object value) {
    return value != null && value.equals(get(rowKey, columnKey));
  }

  /** Remove a row key / column key / value mapping, if present. */
  private boolean removeMapping(
      @CheckForNull Object rowKey, @CheckForNull Object columnKey, @CheckForNull Object value) {

   * not have been inserted consecutively.
   */
  @CheckForNull private final List<NodeConnection<N>> orderedNodeConnections;

  private int predecessorCount;
  private int successorCount;

  private DirectedGraphConnections(
      Map<N, Object> adjacentNodeValues,
      @CheckForNull List<NodeConnection<N>> orderedNodeConnections,
      int predecessorCount,
      int successorCount) {

    this.inverse = inverse;
  }

  // Query Operations (optimizations)

  @Override
  public boolean containsValue(@CheckForNull Object value) {
    return inverse.containsKey(value);
  }

  // Modification Operations

  @CanIgnoreReturnValue
  @Override
  @CheckForNull
  public V put(@ParametricNullness K key, @ParametricNullness V value) {
    return putInBothMaps(key, value, false);
  }

      OutSpliteratorT newFlatMapSpliterator(
          @CheckForNull OutSpliteratorT prefix,
          Spliterator<InElementT> fromSplit,
          Function<? super InElementT, @Nullable OutSpliteratorT> function,
          int splitCharacteristics,
          long estSplitSize);
    }

    @Weak @CheckForNull OutSpliteratorT prefix;
    final Spliterator<InElementT> from;

     * in the value bucket (or vice versa).
     */
    @CheckForNull private final transient ImmutableMapEntry<K, V> nextInKeyBucket;

    NonTerminalImmutableMapEntry(
        K key, V value, @CheckForNull ImmutableMapEntry<K, V> nextInKeyBucket) {
      super(key, value);
      this.nextInKeyBucket = nextInKeyBucket;
    }

    @Override
    @CheckForNull
    final ImmutableMapEntry<K, V> getNextInKeyBucket() {