diff --git a/src/textual/widgets/_help_panel.py b/src/textual/widgets/_help_panel.py
index 1626e75a7f..9ed8421e1b 100644
--- a/src/textual/widgets/_help_panel.py
+++ b/src/textual/widgets/_help_panel.py
@@ -66,6 +66,11 @@ def on_mount(self):
         self.watch(self.screen, "focused", self.update_help)
 
     def update_help(self, focused_widget: Widget | None) -> None:
+        """Update the help for the focused widget.
+
+        Args:
+            focused_widget: The currently focused widget, or `None` if no widget was focused.
+        """
         if not self.app.app_focus:
             return
         self.set_class(focused_widget is not None, "-show-help")