Make old_type optional

server/basicknowledge/migrations/0014_auto_20211129_1038.py

@@ -0,0 +1,18 @@
+# Generated by Django 2.2.24 on 2021-11-29 10:38
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('basicknowledge', '0013_auto_20211110_1140'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='basicknowledge',
+            name='old_type',
+            field=models.CharField(blank=True, choices=[('language_communication', 'Sprache & Kommunikation'), ('society', 'Gesellschaft'), ('interdisciplinary', 'Überfachliches Instrument')], max_length=100),
+        ),
+    ]

server/basicknowledge/models.py

@@ -57,7 +57,8 @@ class BasicKnowledge(StrictHierarchyPage):
 
     old_type = models.CharField(
         max_length=100,
-        choices=InstrumentType.CATEGORY_CHOICES
+        choices=InstrumentType.CATEGORY_CHOICES,
+        blank=True
     )
 
     content_panels = [

server/rooms/wagtail_hooks.py

@@ -34,6 +34,9 @@ def get_room_blocks(page):
 
 
 def get_block_from_stream_data(stream_data, block_name):
+    if len(stream_data) == 0:
+        return []
+
     if isinstance(stream_data[0], tuple):
         return [block for block in stream_data if block[0] in [block_name]]
     if isinstance(stream_data[0], dict):