langchain/tools/google_serper/tool.py/GoogleSerperResults/_arun
class GoogleSerperResults:    async def _arun(
        self,
        query: str,
        run_manager: Optional[AsyncCallbackManagerForToolRun] = None,
    ) -> str:
        """Use the tool asynchronously."""

        return (await self.api_wrapper.aresults(query)).__str__()