Merged in fix/handle-none-lus (pull request #305)

Ignore learning units that are none

server/vbv_lernwelt/dashboard/graphql/types/competence.py

@@ -51,10 +51,18 @@ def competences(
         page_id: Page.objects.get(id=page_id).specific.learning_unit
         for page_id in unique_page_ids
     }
-    circles = {lu.id: lu.get_circle() for lu in learning_units.values()}
+    circles = {
+        lu.id: c
+        for lu in learning_units.values()
+        if lu is not None and (c := lu.get_circle()) is not None
+    }
 
     for completion in completions:
         learning_unit = learning_units.get(completion.page.id)
+
+        if not learning_unit:
+            continue
+
         circle = circles.get(learning_unit.id)
 
         combined_id = f"{circle.id}-{completion.course_session.id}"