langchain/retrievers/document_compressors/chain_extract.py/LLMChainExtractor/from_llm
class LLMChainExtractor:    def from_llm(
        cls,
        llm: BaseLanguageModel,
        prompt: Optional[PromptTemplate] = None,
        get_input: Optional[Callable[[str, Document], str]] = None,
        llm_chain_kwargs: Optional[dict] = None,
    ) -> LLMChainExtractor:
        """Initialize from LLM."""
        _prompt = prompt if prompt is not None else _get_default_chain_prompt()
        _get_input = get_input if get_input is not None else default_get_input
        llm_chain = LLMChain(llm=llm, prompt=_prompt, **(llm_chain_kwargs or {}))
        return cls(llm_chain=llm_chain, get_input=_get_input)