Disable command on a map

Hello,
I want to know how to disable a just order on a map
as:
/ban enabled on the world PVP
/ban off the world SPAWN
thank you in advance

PHP:

    public function onCommandChat(PlayerCommandPreprocessEvent $event){
    $player = $event->getPlayer();
    $cmd = explode(" ",strtolower($event->getmessage()));
    if($cmd[0] == "/ban" or $cmd[0] == "/othercommand" or $cmd[0] == "/othercommand" or $cmd[0] == "/othercommand" or $cmd[0] == "/othercommand"){
    if($player->getLevel()->getName() == "Level"){
    $player->sendMessage("§4Not Allowed in This world sorry");
    $event->setCancelled(true);
    }
    }
    }


I have not test code

Thanks, please go twitter ?