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 commodity, the price, the amount of stock and the brand.
The definition of a management class, mainly to complete the sale of goods, statistics and simple management.)