学习视觉爬虫安装selenium时遇到的问题：
Could not fetch URL https://pypi.org/simple/selenium/: There was a problem confirming the ssl certificate:
解决方法：
# 设置自己的代理通过HTTP方式下载
set http_proxy=http://127.0.0.1:7890 & set https_proxy=http://127.0.0.1:7890
pip install selenium
