last_node() — langchain Function Reference

Architecture documentation for the last_node() function in graph.py from the langchain codebase.

Function python LangChainCore Runnables calls 1 called by 3

Entity Profile

LangChainCore→ Runnables→ last_node() — langchain Function Reference

Dependency Diagram

graph TD
  6b97cc3d_1205_0325_4d44_e903570471b2["last_node()"]
  646f3bb5_a594_563e_cfbf_e18bdc9efb90["Graph"]
  6b97cc3d_1205_0325_4d44_e903570471b2 -->|defined in| 646f3bb5_a594_563e_cfbf_e18bdc9efb90
  6764536f_15b8_5436_aa1a_53ff3f1956c2["extend()"]
  6764536f_15b8_5436_aa1a_53ff3f1956c2 -->|calls| 6b97cc3d_1205_0325_4d44_e903570471b2
  5ce5505c_4a08_f190_13f7_65b75fa4fde9["trim_last_node()"]
  5ce5505c_4a08_f190_13f7_65b75fa4fde9 -->|calls| 6b97cc3d_1205_0325_4d44_e903570471b2
  b9f04a0f_6507_1a21_7a91_357a589c2c3a["draw_mermaid()"]
  b9f04a0f_6507_1a21_7a91_357a589c2c3a -->|calls| 6b97cc3d_1205_0325_4d44_e903570471b2
  6607eba9_2327_f10b_2f7a_81bdd9ce1d84["_last_node()"]
  6b97cc3d_1205_0325_4d44_e903570471b2 -->|calls| 6607eba9_2327_f10b_2f7a_81bdd9ce1d84
  style 6b97cc3d_1205_0325_4d44_e903570471b2 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/runnables/graph.py lines 469–479

    def last_node(self) -> Node | None:
        """Find the single node that is not a source of any edge.

        If there is no such node, or there are multiple, return `None`.
        When drawing the graph, this node would be the destination.

        Returns:
            The last node, or None if there is no such node or multiple
            candidates.
        """
        return _last_node(self)