1.Tensorflow what is the difference between None, -1 and ? when specifying tensor shape?
<https://stackoverflow.com/questions/51732686/tensorflow-what-is-the-difference-between-none-1-and-when-specifying-tensor>
2.How to reshape the tensor in keras? <https://stackoverflow.com/questions/49351038/how-to-reshape-the-tensor-in-keras>
3.Where can I find the API documentation of the class Input?<https://stackoverflow.com/questions/43765381/where-can-i-find-the-api-documentation-of-the-class-input>
4.经典模型-2：手把手带你分析、解读ResNet源代码<https://zhuanlan.zhihu.com/p/31502877>
5.keras深度训练1:fit和callback<https://blog.csdn.net/github_36326955/article/details/79794288###>
