超市中商品分为四类，分别是食品、化妆品、日用品和饮料。每种商品都包含商品名称、价格、库存量和品牌等信息。 定义一个管理类，主要完成对商品的销售、统计和简单管理。(There are four kinds of goods in the supermarket, which are food, cosmetics, daily necessities and drinks. Each commodity contains information about the name of the com