diff --git a/py-polars/polars/utils/udfs.py b/py-polars/polars/utils/udfs.py
index c7fa2d4b1947..46c9850c77a3 100644
--- a/py-polars/polars/utils/udfs.py
+++ b/py-polars/polars/utils/udfs.py
@@ -658,7 +658,7 @@ def _matches(
         idx: int,
         *,
         opnames: list[AbstractSet[str]],
-        argvals: list[AbstractSet[Any] | dict[Any, Any]] | None,
+        argvals: list[AbstractSet[Any] | dict[Any, Any] | None] | None,
     ) -> list[Instruction]:
         """
         Check if a sequence of Instructions matches the specified ops/argvals.