public function definition() {
        $mform = $this->_form;

        $data = $this->_customdata['data'];
        $options = $this->_customdata['options'];

        $mform->addElement('filemanager', 'files_filemanager', get_string('files'), null, $options);
        $mform->addElement('hidden', 'returnurl', $data->returnurl);
        if (isset($data->emaillink)) {
            $emaillink = html_writer::link(new moodle_url('mailto:' . $data->emaillink), $data->emaillink);
            $mform->addElement('static', 'emailaddress', '',
                get_string('emailtoprivatefiles', 'moodle', $emaillink));
        }
        $mform->setType('returnurl', PARAM_LOCALURL);

        $this->add_action_buttons(true, get_string('savechanges'));

        $this->set_data($data);
    }