protected function prepareOptionProgressBar()
    {
        if (!empty($this->progressBar) && is_string($this->progressBar)) {
            return strtr($this->progressBar, ['{LOADING}' => Yii::t($this->translateCategory, 'Loading')]);
        }
        return !empty($this->bootstrapDefaults['progressBar']) ? strtr($this->bootstrapDefaults['progressBar'], ['{LOADING}' => Yii::t($this->translateCategory, 'Loading')]) : '';
    }