【pip报错】Could not fetch URL https://pypi.org/simple/gast/:There was a problem confirming the ssl cert

pip install -r requirements.txt

问题1：

【报错】Could not fetch URL https://pypi.org/simple/gast/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host=‘pypi.org’, port=443): Max retries exceed with url: /simple/gast/ (Caused by SSLError(“Can’t connect to HTTPS URL because the SSL module is not available.”)) - skipping

【原因】国内无法直接访问到pypi，加了豆瓣的源之后就解决了被墙的问题。

【解决方案】

pip install -r requirements.txt -i http://pypi.douban.com/simple --trusted-host pypi.douban.com

问题2

【报错】ERROR: After October 2020 you may experience errors when installing or updating packages. This is because pip will change the way that it resolves dependency conflicts.

We recommend you use --use-feature=2020-resolver to test your packages with the new resolver before it becomes the default.

【原因】pip使用更新的问题，按