protected function definePrevNextActions($doSet = false)
    {
        $actions = new FieldList();
        $prevClass = 'FormAction';

        // do not validate if used in conjonction with zenvalidator
        if (class_exists('FormActionNoValidation')) {
            $prevClass = 'FormActionNoValidation';
        }

        $prev = null;
        if (self::classNameNumber() > 1) {
            $prev = new $prevClass('doPrev', _t('FormExtra.doPrev', 'Previous'));

            $prev->addExtraClass('step-prev');
            $prev->setUseButtonTag(true);
        }

        $label = _t('FormExtra.doNext', 'Next');
        $actions->push($next = new FormAction('doNext', $label));
        $next->setUseButtonTag(true);
        $next->addExtraClass('step-next');
        if (!$prev) {
            $next->addExtraClass('step-next-single');
        }
        if (self::isLastStep()) {
            $next->setTitle(_t('FormExtra.doFinish', 'Finish'));
            $next->addExtraClass('step-last');
        }

        if ($prev) {
            $actions->push($prev);
        }

        $this->addExtraClass('form-steps');

        if (!$doSet) {
            $this->setActions($actions);
            $actions->setForm($this);
        }

        return $actions;
    }