product_list = [    (,),    (,),    (,)]shopping_list =[]salary = ()salary.isdigit():    salary = (salary)    :        index,item (product_list):            (index,item)        user_choice = ()        user_choice.isdigit():            user_choice = (user_choice)            user_choice < (product_list) user_choice >=:                p_item = product_list[user_choice]                p_item[] <= salary:                    shopping_list.append(p_item)                    salary -= p_item[]                    (% p_item,salary)                :                    ()            :                ()        user_choice == :            ()        :            ()