function process($id, $language = null)
    {
        if (!$language && defined('CONTENTFUL_DEFAULT_LANGUAGE')) {
            $language = CONTENTFUL_DEFAULT_LANGUAGE;
        } else {
            $language = 'en-US';
        }
        $this->requestDecorator->setId($id  . '/files/' . $language . '/process');
        $result = $this->client->put($this->requestDecorator->makeResource(), $this->requestDecorator->makePayload(), $this->requestDecorator->makeHeaders());
        $this->refresh();
        return $result;
    }