diff --git a/indico/queries/submission.py b/indico/queries/submission.py
index dbc0aa15..d46f2629 100644
--- a/indico/queries/submission.py
+++ b/indico/queries/submission.py
@@ -456,7 +456,7 @@ class SubmitReview(GraphQLRequest):
     def __init__(
         self,
         submission: Union[int, Submission],
-        changes: Dict | List = None,
+        changes: Union[Dict, List] = None,
         rejected: bool = False,
         force_complete: bool = None,
     ):