/**
  * @param RequestHandler $iForm
  *
  * @return string
  * @throws \Exception
  */
 public function getToken(RequestHandler $iForm)
 {
     try {
         $this->validateEndpoint();
         $params = $this->getParams();
         $result = $this->check($iForm->create(self::$endpoint)->with(http_build_query($params)));
     } catch (\Exception $e) {
         $result = $e->getMessage();
     }
     return $result;
 }