pip install requests 报错 Could not fetch URL https://pypi.python.org/simple/requests/: There was ..r

如题：

pip install requests 报错 :

Could not fetch URL https://pypi.python.org/simple/requests/: There was a problem confirming the ssl certificate: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:600) -skipping Could not find a version that satisfies the requirement requests (from versions: )

No matching distribution found for requests

解决：添加 --trusted-host pypi.python.org ,=> pip  --trusted-host pypi.python.org install  requests 

其他类似问题同样解决。