address type issue caught by mypy in waiting list

Author: RayBB

openlibrary/core/lending.py

@@ -675,7 +675,7 @@ def get_loans_of_user(user_key: str) -> list[Loan]:
         loans += _get_ia_loans_of_user(account.itemname)
     # Set patron's loans in cache w/ now timestamp
     get_cached_loans_of_user.memcache_set(
-        [user_key], {}, loans or [], time.time()
+        (user_key,), {}, loans or [], time.time()
     )  # rehydrate cache
     return loans
 
@@ -702,7 +702,7 @@ def get_user_waiting_loans(user_key: str) -> list[WaitingLoan]:
         itemname = account.itemname if account else None
         result = WaitingLoan.query(userid=itemname)
         get_cached_user_waiting_loans.memcache_set(
-            [user_key], {}, result or {}, time.time()
+            (user_key,), {}, result or [], time.time()
         )  # rehydrate cache
         return result or []
     except JSONDecodeError: