Source code for langchain.chains.graph_qa.base
"""Question answering over a graph."""
from __future__ import annotations
from typing import Any, Dict, List, Optional
from pydantic import Field
from langchain.base_language import BaseLanguageModel
from langchain.callbacks.manager import CallbackManagerForChainRun
from langchain.chains.base import Chain
from langchain.chains.graph_qa.prompts import ENTITY_EXTRACTION_PROMPT, PROMPT
from langchain.chains.llm import LLMChain
from langchain.graphs.networkx_graph import NetworkxEntityGraph, get_entities
from langchain.prompts.base import BasePromptTemplate
[docs]class GraphQAChain(Chain):
    """Chain for question-answering against a graph."""
    graph: NetworkxEntityGraph = Field(exclude=True)
    entity_extraction_chain: LLMChain
    qa_chain: LLMChain
    input_key: str = "query"  #: :meta private:
    output_key: str = "result"  #: :meta private:
    @property
    def input_keys(self) -> List[str]:
        """Return the input keys.
        :meta private:
        """
        return [self.input_key]
    @property
    def output_keys(self) -> List[str]:
        """Return the output keys.
        :meta private:
        """
        _output_keys = [self.output_key]
        return _output_keys
[docs]    @classmethod
    def from_llm(
        cls,
        llm: BaseLanguageModel,
        qa_prompt: BasePromptTemplate = PROMPT,
        entity_prompt: BasePromptTemplate = ENTITY_EXTRACTION_PROMPT,
        **kwargs: Any,
    ) -> GraphQAChain:
        """Initialize from LLM."""
rtdocs_stable/api.python.langchain.com/en/stable/_modules/langchain/chains/graph_qa/base.html