python3 虚拟环境安装requests报错 Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate v

执行 pip install requests 报错如下：

Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:748)'),)': /simple/requests/

解决方案：

pip install request -i http://pypi.douban.com/simple --trusted-host pypi.douban.com