Swift_Mime_SimpleMimeEntity::childSortAlgorithm PHP Метод

    private function childSortAlgorithm($a, $b)
    {
        $typePrefs = array();
        $types = array(strtolower($a->getContentType()), strtolower($b->getContentType()));
        foreach ($types as $type) {
            $typePrefs[] = array_key_exists($type, $this->alternativePartOrder) ? $this->alternativePartOrder[$type] : max($this->alternativePartOrder) + 1;
        }
        return $typePrefs[0] >= $typePrefs[1] ? 1 : -1;
    }