Kelunik\AcmeClient\Stores\KeyStore::__construct PHP Method

    public function __construct($root = "")
    {
        if (!is_string($root)) {
            throw new InvalidArgumentException(sprintf("\$root must be of type string, %s given.", gettype($root)));
        }
        $this->root = rtrim(str_replace("\\", "/", $root), "/");
    }