public function getUnseenMessages($criteria = 'UNSEEN', $fetch_options = null, $fetch_body = true, $fetch_attachment = true, $fetch_flags = true, $limit = null, $page = 1, $charset = "UTF-8") {
        return $this->getMessages($criteria, $fetch_options, $fetch_body, $fetch_attachment, $fetch_flags, $limit, $page, $charset);
    }