pocketmine\event\block\SignChangeEvent::getPlayer PHP Method

    public function getPlayer()
    {
        return $this->player;
    }

 public function onSignChange(SignChangeEvent $event)
 {
     if (strtolower(TextFormat::clean($event->getLine(0))) === "[advancedkits]" and !$event->getPlayer()->hasPermission("advancedkits.admin")) {
         $event->getPlayer()->sendMessage($this->ak->langManager->getTranslation("no-perm-sign"));
         $event->setCancelled();
     }
 }