https://www.cnblogs.com/wanghui-garcia/p/10895397.html
https://www.kaggle.com/isbhargav/guide-to-pytorch-learning-rate-scheduling/notebook#4.-MultiStepLR
https://www.geeksforgeeks.org/adjusting-learning-rate-of-a-neural-network-in-pytorch/
https://pytorch.org/docs/master/optim.html#how-to-adjust-learning-rate