Captioning\File::convertTo PHP Method

    public function convertTo($_output_format)
    {
        $fileFormat = self::getFormat($this);
        $method = strtolower($fileFormat) . '2' . strtolower(rtrim($_output_format, 'File'));
        if (method_exists(new Converter(), $method)) {
            return Converter::$method($this);
        }
        return Converter::defaultConverter($this, $_output_format);
    }