*/
  @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}
   *

      return existing;
    }
    Map<E, LockGraphNode> created = createNodes(clazz);
    existing = (Map<E, LockGraphNode>) lockGraphNodesPerType.putIfAbsent(clazz, created);
    return MoreObjects.firstNonNull(existing, created);
  }

  /**
   * For a given Enum type, creates an immutable map from each of the Enum's values to a
   * corresponding LockGraphNode, with the {@code allowedPriorLocks} and {@code