Swift_Mime_SimpleMimeEntity::getNeededChildLevel PHP Method

    private function getNeededChildLevel($child, $compoundLevel)
    {
        $filter = array();
        foreach ($this->compoundLevelFilters as $bitmask => $rules) {
            if (($compoundLevel & $bitmask) === $bitmask) {
                $filter = $rules + $filter;
            }
        }
        $realLevel = $child->getNestingLevel();
        $lowercaseType = strtolower($child->getContentType());
        if (isset($filter[$realLevel]) && isset($filter[$realLevel][$lowercaseType])) {
            return $filter[$realLevel][$lowercaseType];
        }
        return $realLevel;
    }