Resolve "Not storing groups for documentations is kind of a problem"

Closes #351 (closed)

aleksis/apps/alsijil/model_extensions.py

@@ -2,6 +2,7 @@ from django.db.models import FilteredRelation, Q, QuerySet, Value
 from django.db.models.aggregates import Count, Sum
 from django.utils.translation import gettext as _
 
+from aleksis.apps.chronos.models import LessonEvent
 from aleksis.apps.kolego.models import AbsenceReason
 from aleksis.core.models import Group, Person, SchoolTerm
 
@@ -137,13 +138,6 @@ def annotate_person_statistics_for_school_term(
         datetime_end__date__lte=school_term.date_end,
     )
     if group:
-        documentations = documentations.filter(
-            pk__in=Documentation.objects.filter(course__groups=group)
-            .values_list("pk", flat=True)
-            .union(
-                Documentation.objects.filter(course__groups__parent_groups=group).values_list(
-                    "pk", flat=True
-                )
-            )
-        )
+        lesson_events = LessonEvent.objects.filter(LessonEvent.objects.for_group_q(group))
+        documentations = documentations.filter(amends__in=lesson_events)
     return annotate_person_statistics_from_documentations(persons, documentations)