php - 对象存储的创建方法

Question

创建一个代表商店的对象。让初始化方法获取商店的平方英尺。创建一个可以计算商店电力成本的方法

class Store:
    DOLLARS_PER_KWH = 0.15
    KWH_PER_SQUARE_FOOTAGE_PER_HOUR = 0.19

    def __init__(self): 
        self.square_footage = square_footage

    def cost(self, DOLLARS_PER_KWH, KWH_PER_SQUARE_FOOTAGE_PER_HOUR):
        self.electrical_costs = self * DOLLARS_PER_KWH * KWH_PER_SQUARE_FOOTAGE_PER_HOUR
        print(f' Electrical costs are {self.electrical_costs} dollars.')

我在 init 调用中收到类型错误，以及带有成本的名称错误，这里有什么问题？请帮助编辑我的代码!

Answer 1

 class Store:
        DOLLARS_PER_KWH = 0.15
        KWH_PER_SQUARE_FOOTAGE_PER_HOUR = 0.19

        def __init__(self,square_footage): 
            self.square_footage = square_footage
            Store.DOLLARS_PER_KWH
            Store.KWH_PER_SQUARE_FOOTAGE_PER_HOUR

        def cost(self):
            self.electrical_costs = self.square_footage *Store.DOLLARS_PER_KWH *Store.KWH_PER_SQUARE_FOOTAGE_PER_HOUR
            print ("Electrical costs are $%.2f." % (self.electrical_costs))

    emp1 = Store(10)       
    emp1.cost()