langchain/callbacks/aim_callback.py/AimCallbackHandler/on_llm_start
class AimCallbackHandler:    def on_llm_start(
        self, serialized: Dict[str, Any], prompts: List[str], **kwargs: Any
    ) -> None:
        """Run when LLM starts."""
        aim = import_aim()

        self.step += 1
        self.llm_starts += 1
        self.starts += 1

        resp = {"action": "on_llm_start"}
        resp.update(self.get_custom_callback_meta())

        prompts_res = deepcopy(prompts)

        self._run.track(
            [aim.Text(prompt) for prompt in prompts_res],
            name="on_llm_start",
            context=resp,
        )