Captioning\File::getExpectedCueClass PHP Method

    public static function getExpectedCueClass(FileInterface $_file, $_full_namespace = true)
    {
        $format = self::getFormat($_file) . 'Cue';
        if ($_full_namespace) {
            $tmp = explode('\\', get_class($_file));
            array_pop($tmp);
            $format = implode('\\', $tmp) . '\\' . $format;
        }
        return $format;
    }

 public static function defaultConverter(FileInterface $_file, $_convertTo)
 {
     $subtitleClass = __NAMESPACE__ . '\\Format\\' . ucfirst($_convertTo) . 'File';
     if (!class_exists($subtitleClass)) {
         throw new \InvalidArgumentException(sprintf('Unable to convert to "%s", this format does not exists.', $_convertTo));
     }
     $newSub = new $subtitleClass();
     $cueClass = File::getExpectedCueClass($newSub);
     foreach ($_file->getCues() as $cue) {
         $newSub->addCue($cue->getText(), $cueClass::ms2tc($cue->getStartMS()), $cueClass::ms2tc($cue->getStopMS()));
     }
     return $newSub;
 }