一、问题描述 本机安装的是annaconda的python3.7版本。在下载bar-chart-race出现错误，certifi 2018.8.24为旧版本并且无法卸载。
Found existing installation: certifi 2018.8.24 Cannot uninstall ‘certifi’. 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.
二、解决方法
pip install certifi --ignore-installed而后通过everthing搜索电脑上所有有关certifi 2018.8.24的文件并删除。我的文件位置为
D:\Software\Anaconda3\pkgs\certifi-2018.8.24-py37_1重新安装下bar-chart-race：
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple bar_chart_race