When I was writing a script for dealing with spam on my IMAP server using bogofilter I got to the situation, where I needed to move messages between two folders and I found that the situation is rather complicated, because not all IMAP servers support all required methods. So, I have decided to write a more general solution and submit it to the standard library.
I have never managed to write correct tests for it, and in the end I have not found a time to finish the PR correctly. Would anybody be willing to pick it up and finish it, please?