Need help with plugins

I need help with plugin I Generator Stone please help with how to make the stone end stone and it is still stone as it destroys stone it renews every 3 seconds :

<?php

namespace StoneGenerator;

use pocketmine\plugin\PluginBase as PluginBase;
use pocketmine\event\Listener as Listener;
use pocketmine\utils\TextFormat;
use pocketmine\event\block\BlockBreakEvent;
use pocketmine\block\Block;
use pocketmine\math\Vector3;
use pocketmine\item\Item;

class Main extends PluginBase implements Listener{

public function onEnable(){
$this->getServer()->getPluginManager()->registerEvents($this,$this);
$this->saveDefaultConfig();
$this->getServer()->getLogger()->info(TextFormat::GREEN."[StoneGenerator] Plugin created by SzanelGirl");
}

public function onBreak(BlockBreakEvent $event){
$blok = $event->getBlock();
$gracz = $event->getPlayer();
$y = $blok->getFloorY();
$x = $blok->getFloorX();
$z = $blok->getFloorZ();
if($blok->getId() == 1){
if($gracz->getLevel()->getBlock(new Vector3($x, $y-1, $z))->getId() == 121) {
$event->setCancelled();
$gracz->getInventory()->addItem(Item::get(4, 0, 1));
}else{
$this->getServer()->getScheduler()->cancelTask($data[2]);
$this->finishSchedule($block->getX().":".$block->getY().":".$block->getZ().":".$block->getLevel()->getName());
}
}
}
}

 

What exactly do you mean by that part?

 

replace

PHP:

If($blok->getId()  == 1){

to

PHP:

if ($blok->getId ()  === 121 ) {