'Permanently remove deleted items from selected mailbox.
Generates \'EXPUNGE\' response for each deleted message.
(typ, [data]) = <instance>.expunge()
\'data\' is list of \'EXPUNGE\'d message numbers in order received.'

def expunge(self):

    name = 'EXPUNGE'
    (typ, dat) = self._simple_command(name)
    return self._untagged_response(typ, dat, name)
