diff --git a/scripts/claim_staking_rewards.py b/scripts/claim_staking_rewards.py
index 26b637b..9e4849f 100644
--- a/scripts/claim_staking_rewards.py
+++ b/scripts/claim_staking_rewards.py
@@ -71,7 +71,7 @@
 )
 
 
-def _is_keystore(pkeypath: Path):
+def _is_keystore(pkeypath: Path) -> bool:
     try:
         with open(pkeypath, 'r') as f:
             json.load(f)