public function __construct()
 {
     parent::__construct('Invalid scope.');
 }
 public function __construct()
 {
     parent::__construct('Refresh token is required.');
 }
 public function __construct()
 {
     parent::__construct('Refresh token is invalid.');
 }
 public function __construct()
 {
     parent::__construct('The grant type is required.');
 }