/**
  * Get the api connection
  * @static
  * @return null
  */
 public static function getApi($with_overlay = true)
 {
     $obj = new Mailjet();
     if ($with_overlay) {
         MailjetTemplate::$api = Mailjet_ApiOverlay::getInstance();
         MailjetTemplate::$api->setKeys($obj->getAccountSettingsKey('API_KEY'), $obj->getAccountSettingsKey('SECRET_KEY'));
         MailjetTemplate::$api->secure(false);
     } else {
         MailjetTemplate::$api = new Mailjet_Api($obj->getAccountSettingsKey('API_KEY'), $obj->getAccountSettingsKey('SECRET_KEY'));
     }
     unset($obj);
     return MailjetTemplate::$api;
 }