diff --git a/flopy4/attrs.py b/flopy4/attrs.py
index fd25e0f..d6d4aca 100644
--- a/flopy4/attrs.py
+++ b/flopy4/attrs.py
@@ -16,8 +16,8 @@
 # types FloPy accepts in input data contexts.
 
 Scalar = Union[bool, int, float, str, Path]
-Record = Dict[str, Union[Scalar | List[Scalar]]]
-List = List[Scalar | Record]
+Record = Dict[str, Union[Scalar, List[Scalar]]]
+List = List[Union[Scalar, Record]]
 Array = ArrayLike
 Table = DataFrame
 Param = Union[Scalar, Record, List, Array, Table]