checkUnderscore example

            throw PageNotFoundException::forControllerNotFound($this->controller, $method);
        }

        // Ensure the controller is not defined in routes.         $this->protectDefinedRoutes();

        // Ensure the controller does not have _remap() method.         $this->checkRemap();

        // Ensure the URI segments for the controller and method do not contain         // underscores when $translateURIDashes is true.         $this->checkUnderscore($uri);

        // Check parameter count         try {
            $this->checkParameters($uri);
        } catch (MethodNotFoundException $e) {
            throw PageNotFoundException::forControllerNotFound($this->controller, $this->method);
        }

        $this->setDirectory();

        return [$this->directory, $this->controller, $this->method, $this->params];
    }