解决pip._vendor.urllib3.exceptions.ReadTimeoutError: HTTPSConnectionPool(host='files.pythonhosted.org', port=443): Read timed out.问题

Other mirror sources in China
Tsinghua University https://pypi.tuna.tsinghua.edu.cn/simple/Alibaba
Cloud http://mirrors.aliyun.com/pypi/simple/University of
Science and Technology of China https: //pypi.mirrors. ustc.edu.cn/simple/douban
(douban) http://pypi.douban.com/simple/University of
Science and Technology of China http://pypi.mirrors.ustc.edu.cn/simple/

Download and install selenium 

pip3  install --index-url http://mirrors.aliyun.com/pypi/simple/ selenium