There is absolutely no reason for this class to be a paid class ㅠㅠ It's not that the instructor can't teach or anything, but there is absolutely no reason for this class to be a paid class. I was taking the free class and only did the practical training, so I applied for the paid class (I applied for this class because they said there would be a quiz after each class), but it was no different from the many free classes. The instructor is so-so, but the quality is similar even if you take the free class. For reference, I have taken other paid classes related to programs on Infraon, but this class has the lowest quality..ㅠ.ㅠ