https://qiita.com/birdwatcher/items/b3e4428f63f708db37b7
https://crystal-method.com/topics/transformer-2/
https://qiita.com/birdwatcher/items/b3e4428f63f708db37b7
https://zenn.dev/yukiyada/articles/59f3b820c52571
https://blog.brainpad.co.jp/entry/2021/01/06/113000
https://www.hello-statisticians.com/ml/deeplearning/transformer1.html