diff --git a/stdlib/3/_winapi.pyi b/stdlib/3/_winapi.pyi
index 3b532c6eb..24767ea50 100644
--- a/stdlib/3/_winapi.pyi
+++ b/stdlib/3/_winapi.pyi
@@ -64,7 +64,7 @@ def GetVersion() -> int: ...
 def OpenProcess(desired_access: int, inherit_handle: bool, process_id: int) -> int: ...
 def PeekNamedPipe(handle: int, size: int = ...) -> Union[Tuple[int, int], Tuple[bytes, int, int]]: ...
 def ReadFile(handle: int, size: int, overlapped: Union[int, bool] = ...) -> Tuple[bytes, int]: ...
-def SetNamedPipeHandleState(named_pipe: int, mode: int, max_collection_count: int, collect_data_timeout: int) -> None: ...
+def SetNamedPipeHandleState(named_pipe: int, mode: Optional[int], max_collection_count: Optional[int], collect_data_timeout: Optional[int]) -> None: ...
 def TerminateProcess(handle: int, exit_code: int) -> None: ...
 def WaitForMultipleObjects(handle_seq: Sequence[int], wait_flag: bool, milliseconds: int = ...) -> int: ...
 def WaitForSingleObject(handle: int, milliseconds: int) -> int: ...