orderedNodeConnections.add(new NodeConnection.Pred<>(node));
      }
    }
  }

  @SuppressWarnings("unchecked")
  @Override
  @CheckForNull
  public V addSuccessor(N node, V value) {
    Object previousValue = adjacentNodeValues.put(node, value);
    Object previousSuccessor;

    if (previousValue == null) {
      previousSuccessor = null;