@Override
  public boolean containsKey(@CheckForNull Object key) {
    return asMap().get(key) != null;
  }

  @Override
  public Collection<V> removeAll(@CheckForNull Object key) {
    return MoreObjects.firstNonNull(asMap().remove(key), unmodifiableEmptyCollection());
  }

  Collection<V> unmodifiableEmptyCollection() {
    // These return false, rather than throwing a UOE, on remove calls.

    private AvlNode<E> ceiling(Comparator<? super E> comparator, @ParametricNullness E e) {
      int cmp = comparator.compare(e, getElement());
      if (cmp < 0) {
        return (left == null) ? this : MoreObjects.firstNonNull(left.ceiling(comparator, e), this);
      } else if (cmp == 0) {
        return this;
      } else {
        return (right == null) ? null : right.ceiling(comparator, e);
      }
    }

    private AvlNode<E> ceiling(Comparator<? super E> comparator, @ParametricNullness E e) {
      int cmp = comparator.compare(e, getElement());
      if (cmp < 0) {
        return (left == null) ? this : MoreObjects.firstNonNull(left.ceiling(comparator, e), this);
      } else if (cmp == 0) {
        return this;
      } else {
        return (right == null) ? null : right.ceiling(comparator, e);
      }
    }

        };
      }

      Iterator<Entry<Range<K>, V>> entryIterator() {
        if (subRange.isEmpty()) {
          return emptyIterator();
        }
        Cut<K> cutToStart =
            MoreObjects.firstNonNull(
                entriesByLowerBound.floorKey(subRange.lowerBound), subRange.lowerBound);
        final Iterator<RangeMapEntry<K, V>> backingItr =
            entriesByLowerBound.tailMap(cutToStart, true).values().iterator();

    if (!normalizedAttribute.equals(CHARSET_ATTRIBUTE)) {
      mediaType.parsedCharset = this.parsedCharset;
    }
    // Return one of the constants if the media type is a known type.
    return MoreObjects.firstNonNull(KNOWN_TYPES.get(mediaType), mediaType);
  }

  /**
   * Replaces all parameters with the given attribute with a single parameter with the

      checkArgument(
          (flags >= 0) && (flags <= 0xffff),
          "flags '%s' is out of range (0 <= flags <= 0xffff)",
          flags);

      this.server = MoreObjects.firstNonNull(server, ANY4);
      this.client = MoreObjects.firstNonNull(client, ANY4);
      this.port = port;
      this.flags = flags;
    }

    public Inet4Address getServer() {
      return server;
    }

      L existing = locks.get(index);
      if (existing != null) {
        return existing;
      }
      L created = supplier.get();
      existing = locks.putIfAbsent(index, created);
      return MoreObjects.firstNonNull(existing, created);
    }

    @Override
    public int size() {
      return size;
    }
  }

  /** A bit mask were all bits are set. */
  private static final int ALL_SET = ~0;

        };
      }

      Iterator<Entry<Range<K>, V>> entryIterator() {
        if (subRange.isEmpty()) {
          return emptyIterator();
        }
        Cut<K> cutToStart =
            MoreObjects.firstNonNull(
                entriesByLowerBound.floorKey(subRange.lowerBound), subRange.lowerBound);
        final Iterator<RangeMapEntry<K, V>> backingItr =
            entriesByLowerBound.tailMap(cutToStart, true).values().iterator();

      checkArgument(
          (flags >= 0) && (flags <= 0xffff),
          "flags '%s' is out of range (0 <= flags <= 0xffff)",
          flags);

      this.server = MoreObjects.firstNonNull(server, ANY4);
      this.client = MoreObjects.firstNonNull(client, ANY4);
      this.port = port;
      this.flags = flags;
    }

    public Inet4Address getServer() {
      return server;
    }

   */
  @Override
  public ImmutableSet<V> get(K key) {
    // This cast is safe as its type is known in constructor.
    ImmutableSet<V> set = (ImmutableSet<V>) map.get(key);
    return MoreObjects.firstNonNull(set, emptySet);
  }

  @LazyInit @RetainedWith @CheckForNull private transient ImmutableSetMultimap<V, K> inverse;

  /**
   * {@inheritDoc}
   *