    # File lib/vmail/imap_client.rb, line 140
        def list_mailboxes
          log 'loading mailboxes...'
          @mailboxes ||= (@imap.list("", "*") || []).
            select {|struct| struct.attr.none? {|a| a == :Noselect} }.
            map {|struct| struct.name}.uniq
          @mailboxes.delete("INBOX")
          @mailboxes.unshift("INBOX")
          log "loaded mailboxes: #{@mailboxes.inspect}"
          @mailboxes = @mailboxes.map {|name| mailbox_aliases.invert[name] || name}
          @mailboxes.join("\n")
        end