flashMessageTypeFromImportance example

public function notify(Notification $notification, RecipientInterface $recipient, string $transportName = null): void
    {
        if (null === $request = $this->stack->getCurrentRequest()) {
            return;
        }

        $message = $notification->getSubject();
        if ($notification->getEmoji()) {
            $message = $notification->getEmoji().' '.$message;
        }
        $request->getSession()->getFlashBag()->add($this->mapper->flashMessageTypeFromImportance($notification->getImportance()), $message);
    }

    public function supports(Notification $notification, RecipientInterface $recipient): bool
    {
        return true;
    }
}