安装完毕Certbot后执行出现“ImportError: No module named 'request-packages.urllib3'”
可执行下面的命令解决上面的问题：
pip uninstall urllib3 yum install python-urllib3 -y pip uninstall requests yum remove python-requests yum install python-requests -y yum install certbot -y yum install python2-certbot-nginx -y
