1. pip 使用国内阿里云源

    1. 方式1:

      [root@liqiang.io]# cat ~/.pip/pip.conf
      [global]
      trusted-host =  mirrors.aliyun.com
      index-url = https://mirrors.aliyun.com/pypi/simple
      
    2. 方式2:

      [root@liqiang.io]# pip install --trusted-host mirrors.aliyun.com -i https://mirrors.aliyun.com/pypi/simple flask