linux 下安装有多个python时如何使用某个版本

参考：

https://blog.youkuaiyun.com/dzhongjie/article/details/84404128?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-4.control&dist_request_id=1328642.8007.16155174199213759&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-4.control