langchain/tools/azure_cognitive_services/text2speech.py/AzureCogsText2SpeechTool/_arun
class AzureCogsText2SpeechTool:    async def _arun(
        self,
        query: str,
        run_manager: Optional[AsyncCallbackManagerForToolRun] = None,
    ) -> str:
        """Use the tool asynchronously."""
        raise NotImplementedError("AzureCogsText2SpeechTool does not support async")