Don't take it with Tianshu, he's okay if you go to his office hours, but it is absolutely pointless to go to his discussions, except for the fact that you need to be there for participation.

Tianshu is a nice guy, but a very bad teacher. Even if you meet with him outside of class, he explains ideas/concepts poorly and appears to not understand it himself. Because of this, make sure you read the book and take closely and watch youtube videos on the concepts. While the course itself isn't too bad, not having a teacher places you at a significant disadvantage.