offlineimap and gnus expire flags

[Julien Cubizolles]

To those of you using offlineimap with Gnus, how do you make it
propagate gnus-expire flags (and possibly some other flags)? Does mbsync
handle this problem more easily?

I've tried some offlineimap.py code from
http://roland.entierement.nu/blog/2010/09/08/gnus-dovecot-offlineimap-search-a-howto.html
but it's from 2010 and it's throwing some errors.

--8<---------------cut here---------------start------------->8---
ERROR: ERROR in syncfolder for FreeOffline folder aapt: Traceback (most recent 
call last):
  File "/usr/lib/python2.7/dist-packages/offlineimap/accounts.py", line 450, in 
syncfolder
    remotefolder.syncmessagesto(localfolder, statusfolder)
  File "/usr/lib/python2.7/dist-packages/offlineimap/folder/Base.py", line 549, 
in syncmessagesto
    action(dstfolder, statusfolder)
  File "/usr/lib/python2.7/dist-packages/offlineimap/folder/Base.py", line 484, 
in syncmessagesto_flags
    addflags = selfflags - statusflags
TypeError: unsupported operand type(s) for -: 'list' and 'set'

  unsupported operand type(s) for -: 'list' and 'set'
ERROR: Syncing folder bandsintown [acc: FreeOffline]
  unsupported operand type(s) for -: 'list' and 'set'

Traceback:
  File "/usr/lib/python2.7/dist-packages/offlineimap/folder/Base.py", line 549, 
in syncmessagesto
    action(dstfolder, statusfolder)
  File "/usr/lib/python2.7/dist-packages/offlineimap/folder/Base.py", line 484, 
in syncmessagesto_flags
    addflags = selfflags - statusflags
--8<---------------cut here---------------end--------------->8---