PostSubmitEvent example

            if (null === $viewData && !$this->inheritData) {
                $viewData = $submittedData;
            }
        }

        $this->submitted = true;
        $this->modelData = $modelData;
        $this->normData = $normData;
        $this->viewData = $viewData;

        if ($dispatcher->hasListeners(FormEvents::POST_SUBMIT)) {
            $event = new PostSubmitEvent($this, $viewData);
            $dispatcher->dispatch($event, FormEvents::POST_SUBMIT);
        }

        return $this;
    }

    public function addError(FormError $error): static
    {
        if (null === $error->getOrigin()) {
            $error->setOrigin($this);
        }