diff --git a/stdlib/argparse.pyi b/stdlib/argparse.pyi
index 1243b27dc..06a0dc156 100644
--- a/stdlib/argparse.pyi
+++ b/stdlib/argparse.pyi
@@ -309,7 +309,7 @@ class HelpFormatter:
     def format_help(self) -> str: ...
     def _join_parts(self, part_strings: Iterable[str]) -> str: ...
     def _format_usage(
-        self, usage: str, actions: Iterable[Action], groups: Iterable[_ArgumentGroup], prefix: str | None
+        self, usage: str | None, actions: Iterable[Action], groups: Iterable[_ArgumentGroup], prefix: str | None
     ) -> str: ...
     def _format_actions_usage(self, actions: Iterable[Action], groups: Iterable[_ArgumentGroup]) -> str: ...
     def _format_text(self, text: str) -> str: ...