diff --git a/utils/update_checkout/update_checkout/update_checkout.py b/utils/update_checkout/update_checkout/update_checkout.py
index 6e9f351c637f3..bcdb8e4d300ec 100755
--- a/utils/update_checkout/update_checkout/update_checkout.py
+++ b/utils/update_checkout/update_checkout/update_checkout.py
@@ -16,6 +16,7 @@
 import sys
 import traceback
 from multiprocessing import Lock, Pool, cpu_count, freeze_support
+from typing import Optional
 
 from build_swift.build_swift.constants import SWIFT_SOURCE_ROOT
 
@@ -74,7 +75,7 @@ def check_parallel_results(results, op):
     return fail_count
 
 
-def confirm_tag_in_repo(tag, repo_name):
+def confirm_tag_in_repo(tag, repo_name) -> Optional[str]:
     # type: (str, str) -> str | None
     """Confirm that a given tag exists in a git repository. This function
     assumes that the repository is already a current working directory before