diff --git a/bip-0388/wallet_policies.py b/bip-0388/wallet_policies.py
index 754d201058..43aa54fa50 100755
--- a/bip-0388/wallet_policies.py
+++ b/bip-0388/wallet_policies.py
@@ -68,7 +68,7 @@ def to_descriptor(self) -> str:
 
         # there should not be any remaining "@" expressions
         if desc.find("@") != -1:
-            return Exception("Invalid descriptor template: contains invalid key index")
+            raise Exception("Invalid descriptor template: contains invalid key index")
 
         return desc