Gmail unread counter account pattern

I'm trying to get an unread count for folder "Inbox" in Gmail using an account "[email protected]". The examples imply that this can be done (rather than using an index), but an attempt to do so only yields "unsupported operation: gmail -> [email protected]". Am I doing something wrong?

Sorry for the delay! So this is a bug, i have tested the example "$uc(gmail, updates, count, foo)$" and its actually not working, will fix in 3.23, moving to problems.