The dependency versions of the provided materials are all at a deprecated level. When using the materials with outdated versions provided, convenience functions are difficult to use. Even if fixed, when using vitest in other projects, the vitest version must be changed every time the project is modified. It feels more like reading text with features written down rather than explanations. The time spent understanding by looking at official documentation or understanding by looking at the original module's core-level comments was overwhelmingly longer than the time spent understanding by watching the lecture, which raises questions about why one should watch the lecture. However, the advantage is that it does provide direction. If the majority of Inflearn lectures are like this, I think it's a problem with Inflearn as a whole.