sys

sys用法

https://shockerli.net/post/python3-print/

https://blog.louie.lu/2017/07/26/%E4%BD%A0%E6%89%80%E4%B8%8D%E7%9F%A5%E9%81%93%E7%9A%84-python-%E6%A8%99%E6%BA%96%E5%87%BD%E5%BC%8F%E5%BA%AB%E7%94%A8%E6%B3%95-01-sys/

sys.stdin、sys.stdout和sys.stderr

https://www.itread01.com/content/1544320864.html