function definition() {

        $ui = $this->uistage->get_ui();

        $mform = $this->_form;

        $mform->setDisableShortforms();

        $stage = $mform->addElement('hidden', 'stage', $this->uistage->get_stage());

        $mform->setType('stage', PARAM_INT);

        $stage = $mform->addElement('hidden', $ui->get_name(), $ui->get_uniqueid());

        $mform->setType($ui->get_name(), PARAM_ALPHANUM);

        $params = $this->uistage->get_params();

        if (is_array($params) && count($params) > 0) {

            foreach ($params as $name=>$value) {

                // TODO: Horrible hack, but current backup ui structure does not allow

                // to make this easy (only changing params to objects that would be

                // possible. MDL-38735.

                $intparams = array(

                        'contextid', 'importid', 'target');

                $stage = $mform->addElement('hidden', $name, $value);

                if (in_array($name, $intparams)) {

                    $mform->setType($name, PARAM_INT);

                } else {

                    // Adding setType() to avoid missing setType() warnings.

                    // MDL-39126: support $mform->setType() for additional backup parameters.

                    $mform->setType($name, PARAM_RAW);

                }

            }

        }

    }

$backup = new backup_ui($bc,

         array('id' => $id, 'hubcourseid' => $hubcourseid, 'huburl' => $huburl, 'hubname' => $hubname));