public function getConverter()
    {
        if ($this->_converter === null) {
            $this->_converter = Yii::createObject(AssetConverter::className());
        } elseif (is_array($this->_converter) || is_string($this->_converter)) {
            if (is_array($this->_converter) && !isset($this->_converter['class'])) {
                $this->_converter['class'] = AssetConverter::className();
            }
            $this->_converter = Yii::createObject($this->_converter);
        }

        return $this->_converter;
    }