python中绘制3D图形时，需要绘图模块matplotlib。
执行：
python -mpip install -U pippython -mpip install -U matplotlib
会提示：
Cannot vps云服务器 uninstall ‘six’. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.
只需要把six注释掉不安装就可以了：
sudo python -mpip install -U matplotlib –ignore-installed six
官网：https://matplotlib.org/users/installing.html#macos
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