diff --git a/stdlib/3.4/asyncio/tasks.pyi b/stdlib/3.4/asyncio/tasks.pyi
index d44fe6b37c5a..6fe49fd10718 100644
--- a/stdlib/3.4/asyncio/tasks.pyi
+++ b/stdlib/3.4/asyncio/tasks.pyi
@@ -51,7 +51,7 @@ def run_coroutine_threadsafe(coro: _FutureT[_T],
 def shield(arg: _FutureT[_T], *, loop: AbstractEventLoop = ...) -> Future[_T]: ...
 def sleep(delay: float, result: _T = ..., loop: AbstractEventLoop = ...) -> Future[_T]: ...
 def wait(fs: Iterable[_FutureT[_T]], *, loop: AbstractEventLoop = ...,
-    timeout: float = ...,
+    timeout: Optional[float] = ...,
          return_when: str = ...) -> Future[Tuple[Set[Future[_T]], Set[Future[_T]]]]: ...
 def wait_for(fut: _FutureT[_T], timeout: Optional[float],
              *, loop: AbstractEventLoop = ...) -> Future[_T]: ...