docs: def add_node(self, node_name: str, external_id: Optional[str] = None) -> None:
          """
          Adds the node with the given name to the graph.
  
          Arguments:
              node_name (str): The name of the node to add to the graph.
              external_id (Optional[str]): The external ID of the node.
          """
          self._nodes.add_node_by_name(node_name, external_id)