参考
pyparsing 无法卸载导致安装 matplotlib 出错
解决 Cannot uninstall 'pyparsing' 问题
在安装 pydot 时遇到依赖 pyparsing 无法更新问题：
Successfully built pyparsing
Installing collected packages: pyparsing
Found existing installation: pyparsing 2.0.1
Cannot uninstall 'pyparsing'. 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.
解决方法是手动重装最新版 pyparsing：
sudo pip install -I pyparsing==2.2.0
2019.1