public static function getUrlService($service_name) {
    $url_khipu = 'https://khipu.com/api/' . self::VERSION_KHIPU_SERVICE . '/';

    $services_name = self::getAllServicesName();

    if (array_key_exists($service_name, $services_name)) { 
       $str = $service_name;
       $str[0] = strtolower($str[0]);
       return $url_khipu . (string)$str;
    }
    return FALSE;
  }