public function errorAction()
    {
        if ($this->arguments->getValidationResults()->hasErrors()) {
            $errors = [];
            foreach ($this->arguments->getValidationResults()->getFlattenedErrors() as $propertyName => $propertyErrors) {
                foreach ($propertyErrors as $propertyError) {
                    /** @var \Neos\Error\Messages\Error $propertyError */
                    $error = [
                        'severity' => $propertyError->getSeverity(),
                        'message' => $propertyError->render()
                    ];
                    if ($propertyError->getCode()) {
                        $error['code'] = $propertyError->getCode();
                    }
                    if ($propertyError->getTitle()) {
                        $error['title'] = $propertyError->getTitle();
                    }
                    $errors[$propertyName][] = $error;
                }
            }
            $this->throwStatus(409, null, json_encode($errors));
        }
        $this->throwStatus(400);
    }