ERROR: Could not find a version that satisfies the requirement decorator (from ipython) (from versions: none)
ERROR: No matching distribution found for decorator (from ipython)
pip install ipython -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com
成功安装
提示升级：pip工具升级 ：
python -m pip install -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com --upgrade pip