Resolve "Data checks are also marking empty personal notes and lesson documentations"

Closes #133 (closed)

aleksis/apps/alsijil/data_checks.py

@@ -56,7 +56,7 @@ class NoPersonalNotesInCancelledLessonsDataCheck(DataCheck):
     def check_data(cls):
         from .models import PersonalNote
 
-        personal_notes = PersonalNote.objects.filter(
+        personal_notes = PersonalNote.objects.not_empty().filter(
             lesson_period__substitutions__cancelled=True,
             lesson_period__substitutions__week=F("week"),
             lesson_period__substitutions__year=F("year"),