diff --git a/third_party/2and3/flask/app.pyi b/third_party/2and3/flask/app.pyi
index e4fb038a8..5be3d6d59 100644
--- a/third_party/2and3/flask/app.pyi
+++ b/third_party/2and3/flask/app.pyi
@@ -88,7 +88,7 @@ class Flask(_PackageBoundObject):
     def make_shell_context(self): ...
     env: Optional[str] = ...
     debug: bool = ...
-    def run(self, host: Optional[str] = ..., port: Optional[int] = ..., debug: Optional[bool] = ..., load_dotenv: bool = ..., **options: Any) -> None: ...
+    def run(self, host: Optional[str] = ..., port: Optional[Union[int, str]] = ..., debug: Optional[bool] = ..., load_dotenv: bool = ..., **options: Any) -> None: ...
     def test_client(self, use_cookies: bool = ..., **kwargs: Any) -> FlaskClient: ...
     def test_cli_runner(self, **kwargs: Any): ...
     def open_session(self, request: Any): ...