Add CalendarEntity checks to pylint plugin (#74228)

* Add CalendarEntity checks to pylint plugin

* adjust air_quality ignore

* Mark state property as final

homeassistant/components/calendar/__init__.py

@@ -222,8 +222,9 @@ class CalendarEventDevice(Entity):
             "description": event["description"],
         }
 
+    @final
     @property
-    def state(self) -> str | None:
+    def state(self) -> str:
         """Return the state of the calendar event."""
         if (event := self.event) is None:
             return STATE_OFF
@@ -276,8 +277,9 @@ class CalendarEntity(Entity):
             "description": event.description if event.description else "",
         }
 
+    @final
     @property
-    def state(self) -> str | None:
+    def state(self) -> str:
         """Return the state of the calendar event."""
         if (event := self.event) is None:
             return STATE_OFF

pylint/plugins/hass_enforce_type_hints.py

@@ -591,6 +591,7 @@ _TOGGLE_ENTITY_MATCH: list[TypeHintMatch] = [
     ),
 ]
 _INHERITANCE_MATCH: dict[str, list[ClassTypeHintMatch]] = {
+    # "air_quality": [],  # ignored as deprecated
     "alarm_control_panel": [
         ClassTypeHintMatch(
             base_class="Entity",
@@ -717,6 +718,30 @@ _INHERITANCE_MATCH: dict[str, list[ClassTypeHintMatch]] = {
             ],
         ),
     ],
+    "calendar": [
+        ClassTypeHintMatch(
+            base_class="Entity",
+            matches=_ENTITY_MATCH,
+        ),
+        ClassTypeHintMatch(
+            base_class="CalendarEntity",
+            matches=[
+                TypeHintMatch(
+                    function_name="event",
+                    return_type=["CalendarEvent", None],
+                ),
+                TypeHintMatch(
+                    function_name="async_get_events",
+                    arg_types={
+                        1: "HomeAssistant",
+                        2: "datetime",
+                        3: "datetime",
+                    },
+                    return_type="list[CalendarEvent]",
+                ),
+            ],
+        ),
+    ],
     "cover": [
         ClassTypeHintMatch(
             base_class="Entity",