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The Liskov Substitution Principle (LSP) is one of the basic principles of object-oriented design. The Richter substitution principle says that wherever a base class can appear, subclasses can certainly appear. LSP is the cornerstone of inheritance reuse. Only when derivative classes can replace base classes and the functions of software units are not affected can base classes be truly reused, and derivative classes can also add new behaviors to base classes. The Richter substitution principle is a supplement to the "open-close" principle. The key step to realize the "open-close" principle is abstraction. The inheritance relationship between the base class and the subclass is the concrete realization of abstraction, so the Richter substitution principle is the specification of the concrete steps to realize abstraction. --From BaiduClick "Close Block Editor" and click "Yes" in the pop-up dialog box to exit the "Block Editor".杨长帆淡然道，胡宗宪开始提防我了。李时珍（林文龙 饰）自由沉迷于草药研究之中，他同名为吴慕榕（李诗韵 饰）的女子先前已有婚约，却无法自持的爱上了善良美丽的阿冬（叶璇 饰）。李时珍决定将这份感情埋藏在心底，待科举考试之后向阿冬表白心意，哪知道在阴差阳错之中，他不仅没能够表白，还娶了吴慕榕为妻。1937年底，负责搜罗亚州国家珍贵文物的特务组织“东方史馆”的副馆长山田潜伏在太原，执行一项绝密任务：夺取宁家价值连城的景泰蓝双龙。讲述了退休的体校滑冰教练张胜利，带领着一群非专业的少年们，组建“民间短道速滑队”征战赛场的故事。在他的带领下，几个迷茫的年轻人受到了竞技体育精神的感召，找到了人生的意义，扬帆起航。　　与此同时，富二代金鹏在父亲的催促下，结束了自己混吃等死的“留学生涯”，回到国内，本以为会进入家族企业任职，却没有通过父亲测试，成为一名待业青年。百无聊赖金鹏开始关注国内的直播行业。正巧金鹏注意到了正在直播的安可，安可对砸礼物的金鹏没有多么热情，使从没受到过冷落的富家子弟金鹏产生了兴趣，上演一段爱恨纠葛、惊险刺激、啼笑皆非的青春故事。