diff --git a/stdlib/3/asyncio/events.pyi b/stdlib/3/asyncio/events.pyi
index a2f88dcf8..708cd17c7 100644
--- a/stdlib/3/asyncio/events.pyi
+++ b/stdlib/3/asyncio/events.pyi
@@ -239,7 +239,7 @@ def new_event_loop() -> AbstractEventLoop: ...
 def get_child_watcher() -> Any: ...  # TODO: unix_events.AbstractChildWatcher
 def set_child_watcher(watcher: Any) -> None: ...  # TODO: unix_events.AbstractChildWatcher
 
-def _set_running_loop(loop: AbstractEventLoop) -> None: ...
+def _set_running_loop(loop: Optional[AbstractEventLoop]) -> None: ...
 def _get_running_loop() -> AbstractEventLoop: ...
 
 if sys.version_info >= (3, 7):