diff --git a/docs/core/integration-quality-scale/rules/entity-event-setup.md b/docs/core/integration-quality-scale/rules/entity-event-setup.md
index b03e0010..abddb698 100644
--- a/docs/core/integration-quality-scale/rules/entity-event-setup.md
+++ b/docs/core/integration-quality-scale/rules/entity-event-setup.md
@@ -20,7 +20,7 @@ So we subscribe to the event in `async_added_to_hass` and unsubscribe in `async_
 class MySensor(SensorEntity):
     """Representation of a sensor."""
     
-    unsubscribe: Callable[[], None] = None
+    unsubscribe: Callable[[], None] | None = None
 
     def __init__(self, client: MyClient) -> None:
         """Initialize the sensor."""