diff --git a/zerver/lib/actions.py b/zerver/lib/actions.py
index e08d6c5606..24433b3a98 100644
--- a/zerver/lib/actions.py
+++ b/zerver/lib/actions.py
@@ -1057,7 +1057,7 @@ def do_add_deactivated_redirect(realm: Realm, redirect_url: str) -> None:
     realm.save(update_fields=["deactivated_redirect"])
 
 
-def do_scrub_realm(realm: Realm, acting_user: Optional[UserProfile] = None) -> None:
+def do_scrub_realm(realm: Realm, *, acting_user: Optional[UserProfile]) -> None:
     if settings.BILLING_ENABLED:
         downgrade_now_without_creating_additional_invoices(realm)
 
diff --git a/zerver/tests/test_realm.py b/zerver/tests/test_realm.py
index 4b862bc727..33860f95a9 100644
--- a/zerver/tests/test_realm.py
+++ b/zerver/tests/test_realm.py
@@ -958,7 +958,7 @@ class ScrubRealmTest(ZulipTestCase):
         self.assertNotEqual(CustomProfileField.objects.filter(realm=zulip).count(), 0)
 
         with self.assertLogs(level="WARNING"):
-            do_scrub_realm(zulip)
+            do_scrub_realm(zulip, acting_user=None)
 
         self.assertEqual(Message.objects.filter(sender__in=[iago, othello]).count(), 0)
         self.assertEqual(Message.objects.filter(sender__in=[cordelia, king]).count(), 10)