Fix for recurrence optimizations

aleksis/apps/chronos/managers.py

@@ -9,13 +9,13 @@ from django.db.models.fields import DateField
 from django.db.models.functions import Concat
 
 from calendarweek import CalendarWeek
-from polymorphic.managers import PolymorphicQuerySet
 
 from aleksis.apps.chronos.util.date import week_weekday_from_date, week_weekday_to_date
 from aleksis.apps.cursus.models import Course
 from aleksis.core.managers import (
     AlekSISBaseManagerWithoutMigrations,
     DateRangeQuerySetMixin,
+    RecurrencePolymorphicQuerySet,
     SchoolTermRelatedQuerySet,
 )
 from aleksis.core.models import Group, Person, Room
@@ -866,7 +866,7 @@ class RoomPropertiesMixin:
         return sep.join([room.short_name for room in self.get_rooms()])
 
 
-class LessonEventQuerySet(PolymorphicQuerySet):
+class LessonEventQuerySet(RecurrencePolymorphicQuerySet):
     """Queryset with special query methods for lesson events."""
 
     def for_teacher(self, teacher: Union[int, Person]) -> "LessonEventQuerySet":