Add DummyLabelType model for data import

backend/data_import/migrations/0001_initial.py

@@ -0,0 +1,25 @@
+# Generated by Django 4.0.2 on 2022-05-17 23:01
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+        ("label_types", "0007_delete_relationtypeold"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="DummyLabelType",
+            fields=[],
+            options={
+                "proxy": True,
+                "indexes": [],
+                "constraints": [],
+            },
+            bases=("label_types.categorytype",),
+        ),
+    ]

backend/data_import/models.py

@@ -0,0 +1,10 @@
+from unittest.mock import MagicMock
+
+from label_types.models import CategoryType
+
+
+class DummyLabelType(CategoryType):
+    objects = MagicMock()
+
+    class Meta:
+        proxy = True