langchain/llms/anthropic.py/Anthropic/_acall
class Anthropic:    async def _acall(
        self,
        prompt: str,
        stop: Optional[List[str]] = None,
        run_manager: Optional[AsyncCallbackManagerForLLMRun] = None,
    ) -> str:
        """Call out to Anthropic's completion endpoint asynchronously."""
        stop = self._get_anthropic_stop(stop)
        if self.streaming:
            stream_resp = await self.client.acompletion_stream(
                prompt=self._wrap_prompt(prompt),
                stop_sequences=stop,
                **self._default_params,
            )
            current_completion = ""
            async for data in stream_resp:
                delta = data["completion"][len(current_completion) :]
                current_completion = data["completion"]
                if run_manager:
                    await run_manager.on_llm_new_token(delta, **data)
            return current_completion
        response = await self.client.acompletion(
            prompt=self._wrap_prompt(prompt),
            stop_sequences=stop,
            **self._default_params,
        )
        return response["completion"]