protected static function loadMimeTypes($magicFile)
    {
        if ($magicFile === null) {
            $magicFile = static::$mimeMagicFile;
        }
        $magicFile = Yii::getAlias($magicFile);
        if (!isset(self::$_mimeTypes[$magicFile])) {
            self::$_mimeTypes[$magicFile] = require $magicFile;
        }

        return self::$_mimeTypes[$magicFile];
    }