langchain/chains/llm.py/LLMChain/agenerate
class LLMChain:    async def agenerate(
        self,
        input_list: List[Dict[str, Any]],
        run_manager: Optional[AsyncCallbackManagerForChainRun] = None,
    ) -> LLMResult:
        """Generate LLM result from inputs."""
        prompts, stop = await self.aprep_prompts(input_list, run_manager=run_manager)
        return await self.llm.agenerate_prompt(
            prompts, stop, callbacks=run_manager.get_child() if run_manager else None
        )