I imported my cherry picker script into https://github.com/ python/core-workflow/tree/master/cherry_picker/
Please try it out if you need to do backports for CPython. It still needs some improvement with handling merge conflict, but if you don't anticipate any conflict then it should make things easy for you. (things that do not involve Misc/NEWS, for example)
After the migration, I used it to cherry-pick this PR: https://github.com/python/cpython/pull/670 can confirm it works.
Thanks Nick Coghlan who has started using and contributing to it too :) I believe he has a PR coming soon that adds a --dry-run option, which I look forward to :)