Source code for langchain.chains.qa_with_sources.base
"""Question answering with sources over documents."""
from __future__ import annotations
import inspect
import re
from abc import ABC, abstractmethod
from typing import Any, Dict, List, Optional, Tuple
from langchain.callbacks.manager import (
    AsyncCallbackManagerForChainRun,
    CallbackManagerForChainRun,
)
from langchain.chains import ReduceDocumentsChain
from langchain.chains.base import Chain
from langchain.chains.combine_documents.base import BaseCombineDocumentsChain
from langchain.chains.combine_documents.map_reduce import MapReduceDocumentsChain
from langchain.chains.combine_documents.stuff import StuffDocumentsChain
from langchain.chains.llm import LLMChain
from langchain.chains.qa_with_sources.loading import load_qa_with_sources_chain
from langchain.chains.qa_with_sources.map_reduce_prompt import (
    COMBINE_PROMPT,
    EXAMPLE_PROMPT,
    QUESTION_PROMPT,
)
from langchain.docstore.document import Document
from langchain.pydantic_v1 import Extra, root_validator
from langchain.schema import BasePromptTemplate
from langchain.schema.language_model import BaseLanguageModel
[docs]class BaseQAWithSourcesChain(Chain, ABC):
    """Question answering chain with sources over documents."""
    combine_documents_chain: BaseCombineDocumentsChain
    """Chain to use to combine documents."""
    question_key: str = "question"  #: :meta private:
    input_docs_key: str = "docs"  #: :meta private:
    answer_key: str = "answer"  #: :meta private:
    sources_answer_key: str = "sources"  #: :meta private:
    return_source_documents: bool = False
    """Return the source documents."""
[docs]    @classmethod
    def from_llm(
        cls,