['filter' => FILTER_CALLBACK, 'options' => [self::class, 'checkTextBlob']] ); public function __construct(string $param) { if ($param) // should be empty $this->generate404(); parent::__construct($param); } protected function generate() : void { if (!User::canWriteGuide()) return; $this->result = GuideMgr::createDescription($this->_post['description']); } } ?>