    # File lib/vmail/imap_client.rb, line 590
        def create_if_necessary(mailbox)
          current_mailboxes = mailboxes.map {|m| mailbox_aliases[m] || m}
          if !current_mailboxes.include?(mailbox)
            log "current mailboxes: #{current_mailboxes.inspect}"
            log "creating mailbox #{mailbox}"
            log @imap.create(mailbox)
            @mailboxes = nil # force reload ...
            list_mailboxes
          end
        end