OOP错误：“ TypeError：addBook（）缺少1个必需的位置参数：'cost'”

Question

运行以下代码似乎指示没有足够的参数传递给该类时，我收到以下错误：TypeError：addBook（）缺少1个必需的位置参数：'cost'

我的目标是将标题，作者和费用存储在添加到列表中的单独变量中。我添加了下面两个程序的一部分，这给了我这个问题：

class book:

def __init__(self, title, author, cost, cashBalance, price, titleList, authorList, costList, priceList, sell):
    self.title = title
    self.author = author
    self.cost = cost
    self.cashBalance = 1000
    self.price = price
    self.titleList = []
    self.authorList = []
    self.costList = []
    self.priceList = []
    self.sell = sell

def addBook(self, title, author, cost):
    price = round(cost * 1.1, 2)
    self.titleList.append(title)
    self.authorList.append(author)
    self.costList.append(cost)
    self.priceList.append(price)

下面是使用上面的类代码的程序部分：

from EBS_Class import book as b
play = True
while play == True:    
    decision = input('''Would you like to:
                        A) Add book
                        S) Sell book
                        R) Reduce book prices across board by 2%
                        I) Increase book prices across the board by 2%
                        V) Display inventory
                        W) Write inventory to a file
                        L) Load inventory from an existing file
                        Q) Quit ''')    
    if decision == "A":
        title = input("What is the name of the book you want to add? ")
        author = input("What is the name of the author of the book? ")
        cost = float(input("What is the price of the book? "))
        b.addBook(title, author, cost)