public function sendPurgeRequest($pattern = '')
    {
        if (empty($pattern)) {
            if ($this->config->canPreserveStatic()) {
                $result = $this->api->cleanBySurrogateKey(['text']);
            } else {
                $result = $this->api->cleanAll();
            }
        } elseif (!is_array($pattern) && strpos($pattern, 'http') === 0) {
            $result = $this->api->cleanUrl($pattern);
        } elseif (is_array($pattern)) {
            $result = $this->api->cleanBySurrogateKey($pattern);
        } else {
            return false;
        }
        return $result;
    }