fix

Author: marcoacierno

backend/schedule/models.py

@@ -330,8 +330,8 @@ class ScheduleItem(TimeStampedModel):
     def actual_attendees_total_capacity(self):
         if self.attendees_total_capacity is not None:
             return self.attendees_total_capacity
-        rooms = self.rooms.all()
-        return rooms[0].attendees_total_capacity if rooms else None
+        room = self.rooms.first()
+        return room.attendees_total_capacity if room else None
 
     @cached_property
     def speakers(self):