Disable using Flint and Steel except for TNT

Hey, I've been forgetting everything about PMMP and I needed some reminders on some things like the title...

Could someone please tell me a way to create the following?
Disable usage of flint and steel unless it is on TNT

 

use it in your EventListener / Main file:

PHP:

public function onplayerinteract(pocketmine\event\player\PlayerInteractEvent $event) {
  if(!in_array($event->getAction(), [3,4]) && $event->getBlock()->getId() == 46 && $event->getPlayer()->getInventory()->getItemInHand()->getId() == 259) {
    $event->setCancelled();
    $event->getPlayer()->sendMessage()
  }
}