如何只打破一个嵌套循环？

Question

我的代码如下所示：

shop = input("Do you want to enter the shop?")
    if shop == "y":
        print ("["+shopownername+"]: Welcome to my store.")
        sleep(1)
        print ("["+shopownername+"]: Here are the items for sale:")
        for x in shopitems:
            print (x)
        sleep(1)
        print ("You have "+str(gold)+" gold.")
        sleep(1)
        choice = 0
        while choice != "exit":
            choice = input("What would you like to buy? Type 'exit' and enter to leave.")
            if choice == "a":
                purchase = "a"
                confirm = input("Are you sure you want to buy "+purchase+"? (y/n)")
                if confirm == "y":
                    if "a" in weapons:
                        print ("You already have that.")
                        break
                    elif gold < shopitems[purchase]:
                        print ("You do not have enough gold for that.")
                        break
                    else:
                        gold = gold - shopitems[purchase]
                        weapons.append("a")
                        print ("You have purchased the "+purchase+".")
                        print ("You now have "+str(gold)+" gold.")
                        break
            elif choice == "b":
                purchase = "b"
                confirm = input("Are you sure you want to buy "+purchase+"? (y/n)")
                if confirm == "y":
                    if "b" in weapons:
                        print ("You already have that.")
                        break
                    elif gold < shopitems[purchase]:
                        print ("You do not have enough gold for that.")
                        break
                    else:
                        gold = gold - shopitems[purchase]
                        weapons.append("b")
                        print ("You have purchased the "+purchase+".")
                        print ("You now have "+str(gold)+" gold.")
                        break
        else:
            print ("["+shopownername+"]: Thank you for coming.")
    else:
        print ("You did not enter the shop.")

它应该做的是，在任何情况下，直到您退出商店，您将能够购买物品。然而，在这个系统中，它也打破了时间，并继续下一段代码。我应该做的是尝试买一个，无论我买不起，已经拥有它，或买了它，都可以试图买b或者试图重新购买。 我该怎么办？