I was trying to diagnose a problem and discovered a couple of small issues with pykolab/imap/dovecot.py
There is no quote function defined in the module. I assume it was intended to act like folder_quote from imap/__init__.py (though I wasn't sure how to access that, I tried self.folder_quote but that triggered an IMAP command.)
dovecot imap complained about seeing two slashes in a row.
in dovecot.py the calls to _simple_command for SETMETADATA construct the path "/private/%s" however calls in imap/__init__.py to metdata_path.replace('/shared/', '/') or ('/private/', '/') combined with the path construction you end up with /private//vendor/kolab.
My quick patch is in https://git.kolab.org/P15
quote probably should be a function
removing the extra / could either be what I did or replacing the replace with replace('/shared/', ''). Not sure which you'd prefer.