public static function get_options_array(\core_customfield\field_controller $field) : array {
        if ($field->get_configdata_property('options')) {
            $options = preg_split("/\s*\n\s*/", trim($field->get_configdata_property('options')));
        } else {
            $options = array();
        }
        return array_merge([''], $options);
    }