addNode

addNode<
  K extends string,
  NodeMap extends Record<K, NodeAction<S, U, C, InterruptType, WriterType>>
>(
  nodes: NodeMap
): StateGraph<SD, S, U, N | K, I, O, C, MergeReturnType<NodeReturnType, { [key in string | number | symbol]: NodeMap[key] extends NodeAction<S, U, C, InterruptType, WriterType>  U : never }>>