diff --git a/src/textual/widget.py b/src/textual/widget.py
index 608794e0f3..0f1fa9c6c4 100644
--- a/src/textual/widget.py
+++ b/src/textual/widget.py
@@ -636,7 +636,8 @@ def set_loading(self, loading: bool) -> Awaitable:
                 if child.has_class(LOADING_INDICATOR_CLASS):
                     return child.remove()
 
-            async def dummy(): ...
+            async def dummy() -> None:
+                """Do nothing if there is no indicator."""
 
             return dummy()