python pytest 安装失败解决办法 No matching distribution found for pytest Could not find a version that sa

 pip install pytest

报错信息

ERROR: Could not find a version that satisfies the requirement pytest
ERROR: No matching distribution found for pytest

解决办法，使用镜像安装，万事大吉！

pip install pytest -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com