diff --git a/aleksis/apps/alsijil/schema.py b/aleksis/apps/alsijil/schema.py
index e09159f5be8a4dfeaea6c0818a0320a04e6eb107..559169a5bb66371e077509c0aaeda5210f3bf909 100644
--- a/aleksis/apps/alsijil/schema.py
+++ b/aleksis/apps/alsijil/schema.py
@@ -96,11 +96,11 @@ class LessonDocumentationMutation(graphene.Mutation):
             extra_lesson=extra_lesson
         )
 
-        if topic:
+        if topic is not None:
             lesson_documentation.topic = topic
-        if homework:
+        if homework is not None:
             lesson_documentation.homework = homework
-        if group_note:
+        if group_note is not None:
             lesson_documentation.group_note = group_note
 
         lesson_documentation.save()