>> the twisted imap API is problematic for imaplib because twisted seems to expect its arguments to already be Python unicode.

>Could you elaborate on this?  As far as I can tell, it works fine:

I wasn't addressing encode/decode specifically. Both twisted and PloneMailList offer implementations with same encoding name, "imap4-utf-7".

I meant that it's difficult for the twisted API to inform what might be done for imaplib since twisted takes full unicode but imaplib expects only unicode-ASCII subset.

The first part of jamesh's original issue is just encoder/decoder, so either twisted or PloneMailList would seem to suffice. I was addressing jamesh's second part whether "optionally if imaplib would perform the encoding and decoding at the appropriate points."

Point 2 of my response seems the more difficult. imaplib list and lsub return str instances with ASCII + utf-7 stuffed together. (twisted avoids this by returning tuples of unicode, if I understand correctly).