use sys.version_info tuple instead of minor attribute

Author: spokeydokeys

src/openai/_utils/_sync.py

@@ -12,7 +12,9 @@
 
 
 
-if sys.version_info.minor < 9:
+if sys.version_info >= (3, 9):
+    to_thread: Callable[..., Awaitable[Any]] = asyncio.to_thread
+else:
     async def _to_thread(
         func: Callable[..., Any], /, *args: List[Any], **kwargs: Dict[str, Any]
     ) -> Any:
@@ -31,8 +33,6 @@ async def _to_thread(
         return await loop.run_in_executor(None, func_call)
 
     to_thread: Callable[..., Awaitable[Any]] = _to_thread
-else:
-    to_thread: Callable[..., Awaitable[Any]] = asyncio.to_thread # type: ignore - to_thread is only defined in python 3.9+
 
 # copied from `asyncer`, https://github.com/tiangolo/asyncer
 def asyncify(