LengthChatModel Class — langchain Architecture

Architecture documentation for the LengthChatModel class in test_history.py from the langchain codebase.

Class python

Entity Profile

Dependency Diagram

graph TD
  4e783b0f_b048_86db_19ed_af86b855def4["LengthChatModel"]
  48aa29b8_65e7_522f_a445_a441eeb6baff["BaseChatModel"]
  4e783b0f_b048_86db_19ed_af86b855def4 -->|extends| 48aa29b8_65e7_522f_a445_a441eeb6baff
  0af0dfde_fe33_f3e5_b5e6_a3d18260dc67["test_history.py"]
  4e783b0f_b048_86db_19ed_af86b855def4 -->|defined in| 0af0dfde_fe33_f3e5_b5e6_a3d18260dc67
  3fca6306_e829_107e_b059_5c8f66b2aeea["_generate()"]
  4e783b0f_b048_86db_19ed_af86b855def4 -->|method| 3fca6306_e829_107e_b059_5c8f66b2aeea
  53c1d076_8d91_55b4_cedb_6d6f1318aba4["_llm_type()"]
  4e783b0f_b048_86db_19ed_af86b855def4 -->|method| 53c1d076_8d91_55b4_cedb_6d6f1318aba4

Relationship Graph

Source Code

libs/core/tests/unit_tests/runnables/test_history.py lines 281–299

class LengthChatModel(BaseChatModel):
    """A fake chat model that returns the length of the messages passed in."""

    @override
    def _generate(
        self,
        messages: list[BaseMessage],
        stop: list[str] | None = None,
        run_manager: CallbackManagerForLLMRun | None = None,
        **kwargs: Any,
    ) -> ChatResult:
        """Top Level call."""
        return ChatResult(
            generations=[ChatGeneration(message=AIMessage(content=str(len(messages))))]
        )

    @property
    def _llm_type(self) -> str:
        return "length-fake-chat-model"