I just skimmed through the article and immediately noticed that the code was taken from Andrej Karpathy's lectures [0][1]. This is not a bad thing since the author included the bibliography. BTW, the author should replace "Andrej Karaphy".

[0] https://karpathy.ai/zero-to-hero.html [1] https://www.youtube.com/watch?v=VMj-3S1tku0