里氏替换原则是面向对象编程中的一个基本概念，确保派生类可以替代其基类使用，而不会改变程序的正确性。
The Liskov Substitution Principle is a fundamental concept in object-oriented programming, ensuring that derived classes can be used in place of their base classes without altering the correctness of the program.
Your time is limited, don’t waste it living someone else’s life.
释义：人的行为必须与自然规律相协调，才能取得成功。这句话强调人与自然的和谐关系。
"A library is a place where the past meets the present and the future."