Fix faulty default value declaration for ISBN of licenses

server/users/migrations/0033_alter_license_isbn.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.2.13 on 2022-07-15 15:51
+
+from django.db import migrations, models
+import users.licenses
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('users', '0032_alter_license_isbn'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='license',
+            name='isbn',
+            field=models.CharField(default=users.licenses.get_default_isbn, max_length=50),
+        ),
+    ]

server/users/models.py

@@ -314,7 +314,7 @@ class License(models.Model):
     order_id = models.IntegerField(blank=False, null=False, default=-1)
     raw = models.TextField(default='')
     isbn = models.CharField(max_length=50, blank=False, null=False,
-                            default=get_default_isbn())  # student license
+                            default=get_default_isbn)  # student license
     created_at = models.DateTimeField(auto_now_add=True)
     hep_created_at = models.DateTimeField(default=AWARE_NO_DATETIME)
     new_api_raw = models.TextField(default='')