python2.7爬https页面报错

python2.7使用requests爬取https页面时报错：

解决方法：

`sudo pip install pyOpenSSL cryptography idna certifi --upgrade`
`sudo pip install urllib3[secure] --upgrade`
`sudo pip install requests[security] --upgrade`

详见：https://www.franzoni.eu/python-requests-ssl-and-insecureplatformwarning/