Python中三级菜单 选择进入各级菜单

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三级菜单 选择进入各级 
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chinaMenu = {
	"菜谱大全":{
		"家常菜谱":{
			"家常菜":{"糖醋排骨","红烧排骨"},
			"凉菜":{"麻辣鸡丝","凉拌黄瓜"}
		},
		"各地小吃":{
			"四川小吃":{"四川凉面","麻辣香锅"},
			"广东小吃":{"鲜虾肠粉","云吞面","肉香糯米团"}
		}
	},
	"健康饮食":{
		"饮食健康":{
			"家常菜":{"糖醋排骨","红烧排骨"},
			"凉菜":{"麻辣鸡丝","凉拌黄瓜"}
		},
		"人群膳食":{
			"孕妇":{"鸽子汤","红烧猪蹄"},
			"产妇":{"猪脚姜","鲫鱼汤","猪蹄花生汤"}
		}
	}
}

exit_flag = False
while not exit_flag:
	for i in chinaMenu:
		print(i)
	bigMenu = input("请输入需要进入的栏目：")
	if bigMenu in chinaMenu:
		while not exit_flag:
			for i in chinaMenu[bigMenu]:
				print(i)
			smallMenu = input("请输入需要进入的栏目：")
			if smallMenu in chinaMenu[bigMenu]:
				while not exit_flag:
					for i in chinaMenu[bigMenu][smallMenu]:
						print(i)
					ultimateMenu = input("请输入需要进入的栏目：")
					if ultimateMenu in chinaMenu[bigMenu][smallMenu]:
						while not exit_flag:
							for i in chinaMenu[bigMenu][smallMenu][ultimateMenu]:
								print(i)
							choice = input("已经最终栏目了，请输入B返回，如果需要退出请选择Q：")
							if choice == "B":
								break
							if choice == "Q":
								exit_flag = True
					if ultimateMenu == "B":
						break
					if ultimateMenu == "Q":
						exit_flag = True
			if smallMenu == "B":
				break
			if smallMenu == "Q":
				exit_flag = True
	if bigMenu == "B":
		break
	if bigMenu == "Q":
		exit_flag = True