diff --git a/libs/langgraph/tests/any_str.py b/libs/langgraph/tests/any_str.py
index 66dc381b7..9a1977a8c 100644
--- a/libs/langgraph/tests/any_str.py
+++ b/libs/langgraph/tests/any_str.py
@@ -1,9 +1,9 @@
 import re
-from typing import Any, Sequence
+from typing import Any, Sequence, Union
 
 
 class AnyStr(str):
-    def __init__(self, prefix: str | re.Pattern = "") -> None:
+    def __init__(self, prefix: Union[str, re.Pattern] = "") -> None:
         super().__init__()
         self.prefix = prefix