public implementation reading list: https://tensorflow.google.cn/tutorials/text/transformer#%E9%81%AE%E6%8C%A1%EF%BC%88masking%EF%BC%89\\ https://github.com/jason9693/MusicTransformer-tensorflow2.0\\ https://arxiv.org/abs/1809.04281\\
public implementation reading list: https://tensorflow.google.cn/tutorials/text/transformer#%E9%81%AE%E6%8C%A1%EF%BC%88masking%EF%BC%89\\ https://github.com/jason9693/MusicTransformer-tensorflow2.0\\ https://arxiv.org/abs/1809.04281\\