python安装xpath的时候遇到错误：
Collecting xpath
Could not find a version that satisfies the requirement xpath (from versions: )
No matching distribution found for xpath
You are using pip version 10.0.1, however version 18.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.
解决方法:
打开cmd——输入 “python -m pip install --upgrade pip” ——等待升级
成功后如下图：
重新setting中安装即可