Standard Description: The default assumption is that videos are optional because they cover the same material discussed in some combination of class, recitation section, and the written reading notes. They can nonetheless serve as a useful resource if you are confused on a topic. We might occasionally "assign" a small number of videos in order to let class focus more on specific topics. We may also point interested students to a small number of "optional" videos on related but less-essential topics.
Special note for this section: The videos assume an order where type inference precedes ML modules, but we went in the other order. It should not matter much, if at all. Below I have listed the videos in the order we did the material, but you will see the file names assume a different order. (We switched the order to align better with the lecture/section schedule.)