python使用面向对象的方式，完成大白想吃饭，不会做，去找大红做饭的场景

# coding:utf-8

class Human(object):
    def __init__(self, name):
        self.name = name

    def speak(self, words):
        print self.name, 'say', words

class Boy(Human):
    def buy_food(self, food):
        print self.name, 'buy', food

class Girl(Human):
    def cook_food(self, food):
        print self.name, 'go to cook', food

class SalesPerson(Human):
    price_sheet = None

    def check(self, good_name):
        price = self.price_sheet.get(good_name)
        if not price:
            self.speak('sorry,没有'%s % good_name)
            return
        self.speak('%s卖%s钱' % (good_name, price))
        return price

    def sale(self, good_name, money):
        Food = self.good_sheet.get(good_name)
        food = Food(good_name, money)
        self.speak('给你%s' % food)
        return food



class Food(object):
    def __init__(self, name, price):
        self.name = name
        self.price = price
    def __str__(self):
        return '%s价格：%s' % (self.name, self.price)



class Vegetable(Food):
    pass


class Meat(Food):
    pass

dabai = Boy('dabai')
dahong = Girl('dahong')

dabai.speak('我饿了,想吃饭不会做,大红可以帮我吗？')
dahong.speak('可以，你去买菜吧')
dahong.speak('一颗白菜，一斤肉')

check_list = ['白菜', '五花肉']
sales = SalesPerson('卖菜的')
sales.price_sheet = {
        '白菜': 3,
        '五花肉': 15,
    }

sales.good_sheet = {
        '白菜': Vegetable,
        '五花肉':Meat
    }
food_list = []
for food_name in check_list:
    dabai.buy_food(food_name)
    price = sales.check(food_name)
    if price:
        food = sales.sale(food_name, price)
        food_list.append(food)
for food in food_list:
    dahong.cook_food(food)