Update helper_functions.py

helper_functions.py

@@ -268,7 +268,7 @@ async def check_validity(query: str, keyword_search: BM25L) -> np.ndarray:
         )
 
 
-def is_cheapest(query: str, request_json: list) -> list:
+async def is_cheapest(query: str, request_json: list) -> list:
     """
     Check which product is the cheapest within the same category as
     each input query.