public function __construct($realm, $error, $error_description, $scope, $http_error)
 {
     parent::__construct($http_error, self::DirectResponseContentType);
     $this->realm = $realm;
     $this->error = $error;
     $this->error_description = $error_description;
     $this->scope = $scope;
     $this->http_error = $http_error;
 }
 public function __construct()
 {
     // Successful Responses: A server receiving a valid request MUST send a
     // response with an HTTP status code of 200.
     parent::__construct(self::HttpOkResponse, self::DirectResponseContentType);
 }