diff --git a/stdlib/2and3/sched.pyi b/stdlib/2and3/sched.pyi
index b8e7b2b0a..5d5cf33d2 100644
--- a/stdlib/2and3/sched.pyi
+++ b/stdlib/2and3/sched.pyi
@@ -1,5 +1,5 @@
 import sys
-from typing import Any, Callable, Dict, List, NamedTuple, Text, Tuple
+from typing import Any, Callable, Dict, List, NamedTuple, Optional, Text, Tuple
 
 Event = NamedTuple('Event', [
     ('time', float),
@@ -14,12 +14,12 @@ class scheduler:
         def __init__(self, timefunc: Callable[[], float] = ..., delayfunc: Callable[[float], None] = ...) -> None: ...
         def enterabs(self, time: float, priority: Any, action: Callable[..., Any], argument: Tuple[Any, ...] = ..., kwargs: Dict[str, Any] = ...) -> Event: ...
         def enter(self, delay: float, priority: Any, action: Callable[..., Any], argument: Tuple[Any, ...] = ..., kwargs: Dict[str, Any] = ...) -> Event: ...
-        def run(self, blocking: bool = ...) -> float: ...
+        def run(self, blocking: bool = ...) -> Optional[float]: ...
     else:
         def __init__(self, timefunc: Callable[[], float], delayfunc: Callable[[float], None]) -> None: ...
         def enterabs(self, time: float, priority: Any, action: Callable[..., Any], argument: Tuple[Any, ...]) -> Event: ...
         def enter(self, delay: float, priority: Any, action: Callable[..., Any], argument: Tuple[Any, ...]) -> Event: ...
-        def run(self) -> float: ...
+        def run(self) -> None: ...
 
     def cancel(self, event: Event) -> None: ...
     def empty(self) -> bool: ...