function deletebyMimeModule(&$mimetype_object, $force = false) {
        if (strtolower(get_class($mimetype_object)) != 'xoopsmimetypes_perms') {
            return false;
        }
        $sql = sprintf("DELETE FROM %s WHERE mperm_mime = %u AND mperm_module = %u", $this->db->prefix("mimetypes_perms"), $mimetype_object->getVar('mperm_mime'), $mimetype_object->getVar('mperm_module'));