public function purgeUrls(array $urls)
    {
        if (strpos($this->domain, 'http') === false) {
            throw new \InvalidArgumentException("'domain' is not configured for fastly driver");
        }

        if (strpos($this->domain, 'http') !== 0) {
            throw new \InvalidArgumentException("'domain' must include the protocol, e.g. http://www.foo.com");
        }

        foreach ($urls as $url) {
            if (!$this->sendRequest('PURGE', $this->domain . $url)) {
                return false;
            }
        }

        return true;
    }