add async for python repl (#9080)

libs/langchain/langchain/tools/python/tool.py

@@ -131,3 +131,15 @@ class PythonAstREPLTool(BaseTool):
                 return io_buffer.getvalue()
         except Exception as e:
             return "{}: {}".format(type(e).__name__, str(e))
+
+    async def _arun(
+        self,
+        query: str,
+        run_manager: Optional[AsyncCallbackManagerForToolRun] = None,
+    ) -> Any:
+        """Use the tool asynchronously."""
+
+        loop = asyncio.get_running_loop()
+        result = await loop.run_in_executor(None, self._run, query)
+
+        return result