diff --git a/api/preprints/serializers.py b/api/preprints/serializers.py
index 265fa64a9b5..bdf8e0ad5e5 100644
--- a/api/preprints/serializers.py
+++ b/api/preprints/serializers.py
@@ -406,7 +406,7 @@ def handle_author_assertions(self, preprint, validated_data, auth):
             'why_no_prereg',
             'prereg_links',
             'has_prereg_links',
-            'prereg_link_info'
+            'prereg_link_info',
         }
         if author_assertions & validated_data.keys():
             if not preprint.is_admin_contributor(auth.user):