public static function getDataApi()
 {
     $obj = new Mailjet();
     if (self::$data_api === null) {
         self::$data_api = mailjetdata::getInstance();
         self::$data_api->setKeys($obj->getAccountSettingsKey('API_KEY'), $obj->getAccountSettingsKey('SECRET_KEY'));
     }
     return self::$data_api;
 }
 /**
  * Singleton pattern :
  * Get the instance of the object if it already exists
  * or create a new one.
  *
  * @access	public
  * @uses	MailjetData::$_instance
  *
  * @return resource instance
  */
 public static function getInstance()
 {
     if (!self::$_instance instanceof self) {
         self::$_instance = new self();
     }
     return self::$_instance;
 }