Use teachers from lesson events instead of from courses

aleksis/apps/alsijil/schema/documentation.py

@@ -54,7 +54,7 @@ class DocumentationType(PermissionsTypeMixin, DjangoFilterMixin, DjangoObjectTyp
     def resolve_teachers(root: Documentation, info, **kwargs):
         if not str(root.pk).startswith("DUMMY") and hasattr(root, "teachers"):
             return  root.teachers
-        return root.course.teachers
+        return root.lesson_event.teachers
 
     @classmethod
     def get_queryset(cls, queryset, info):
@@ -182,7 +182,7 @@ class DocumentationBatchCreateOrUpdateMutation(graphene.Mutation):
             if doc.teachers is not None:
                 obj.teachers.add(*doc.teachers)
             else:
-                obj.teachers.set(lesson_event.course.teachers)
+                obj.teachers.set(lesson_event.teachers)
             obj.save()
             return obj
         else: