出错提示见后面，解决方法为
因此命令可以使用（原先使用的命令：pip install pymysql）：
pip install pymysql -i http://pypi.douban.com/simple/ –trusted-host pypi.douban.com
或者
pip3 install pymysql -i http://pypi.douban.com/simple/ –trusted-host pypi.douban.com
错误提示：
[root@centos7-64 mihaoyun]# pip install pymysql
WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None=None)) after connection broken by ‘NewConnectionError(‘: Failed to est new connection: [Errno 101] 网络不可达’,)’: /simple/pymysql/
WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None=None)) after connection broken by ‘NewConnectionError(‘: Failed to est new connection: [Errno 101] 网络不可达’,)’: /simple/pymysql/
WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None=None)) after connection broken by ‘NewConnectionError(‘: Failed to est new connection: [Errno 101] 网络不可达’,)’: /simple/pymysql/
WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None=None)) after connection broken by ‘NewConnectionError(‘: Failed to est new connection: [Errno 101] 网络不可达’,)’: /simple/pymysql/
WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None=None)) after connection broken by ‘NewConnectionError(‘: Failed to est new connection: [Errno 101] 网络不可达’,)’: /simple/pymysql/
ERROR: Could not find a version that satisfies the requirement pymysql (sions: none)
ERROR: No matching distribution found for pymysql