public function addUrl($url, $kind = Url::CALLBACK)
    {
        if ($this->urls == null) {
            $this->urls = [];
        }

        $this->urls[] = new Url($url, $kind);

        return $this;
    }
public function addUrl($url, $kind = Url::CALLBACK)
    {
        if ($this->urls == null) {
            $this->urls = [];
        }

        $this->urls[] = new Url($url, $kind);

        return $this;
    }
@param string $url
@param string $kind

@return Transaction