Thank you for your valuable evaluation. When I create a lecture, the thing that concerns me the most is how much the students will understand and grasp the lecture content when they listen to my lecture. So, as I try to explain the content easily, the lecture explanation increases and the debugging process becomes longer, so the lecture time becomes longer overall. However, I would appreciate it if you understand that I put a lot of effort into it. As you said, if you accurately understand the flow at the source code level, I think you will be able to freely expand and apply not only the basic technology of OAuth2, but also the basic functions. It is a pretty long lecture, but we are already halfway through. I hope you will run to the end.~~