我正在遵循有关设置班级的教程，以制作酒吧账单为例，但无法弄清楚为什么在向账单中添加新项目时出现错误

‘dict’对象没有属性’append’

编码

class Bar_tab:

    #dictionary
    menu = {
        'wine':5,
        'beer':2,
        'coke':3,
        'chicken':9,
        'dessert':7
    }

    #set up the class
    def __init__(self):
        #set up empty initial total and item list
        #customer will add items and total will add up
        #these variables will exist within the class
        self.total = 0
        self.items = {}

    #function for add items to tab
    def add(self,item):
        self.items.append(item)
        #add the value from menu dictionary for the 'item'
        self.total += self.menu[item]

    def pay_bill (self,tax,service):
        #tax will only exist within this function in the class
        tax=(tax/100) *self.total
        service=(service/100)*self.total
        total=self.total + tax + service

        for items in self.items:
            print(f'{item} ${self.menu[item]}')

        print(f'Total is ${total}')`

错误self.items.append(item)在线