更改Ubuntu系統中默認的Python版本
sudo update-alternatives --install /usr/bin/python python /usr/bin/python3.6 2
sudo update-alternatives --install /usr/bin/python python /usr/bin/python3.6 2
https://www.bilibili.com/video/BV1k8411575T/?vd_source=d68ed178f151e80fea1e02efd205802c