Thanks to this lecture, I was able to neatly organize how core keywords such as object-oriented, inheritance, and polymorphism penetrate the development philosophy, which was really great. Since everyone kept praising it, my review is not special, but it is true that it was really good, and now, if I just study the lecture examples repeatedly and establish OCP as my habit, it will greatly help me improve my productivity. Thank you for the great lecture, and I will continue to work hard in the future! Oh, and I will keep waiting! Until the intermediate and advanced versions come out :) You already have a lot of high-quality lectures, but I believe that if the instructor is happy, even better lectures will come out :)