Solved How to delete world from the worlds folder

Hi guys, I'm trying to delete a world inside to worlds folder, but it doesn't work, there isn't even a error message.

PHP:

$lvl = $player->getLevel();
                    $folder = $lvl->getProvider()->getPath();
                    $this->plugin->getServer()->unloadLevel($lvl);
                    $server = $this->plugin->getServer()->getDataPath();

                    echo $folder;

                    $player->teleport($this->plugin->getServer()->getDefaultLevel()->getSafeSpawn());
                    $this->plugin->getServer()->getScheduler()->scheduleDelayedTask(new DelayedDeleteDir($this->plugin, $folder), 40);

PHP:

<?php

namespace CWTraining\tasks;

use CWTraining\CWTraining;
use pocketmine\scheduler\Task;

class DelayedDeleteDir extends Task{
    public $plugin;
    public $dir;

    public function __construct(CWTraining $plugin, string $dir) {
        $this->plugin = $plugin;
    }

    public function onRun(int $currentTick) {
        $this->plugin->delete_files($this->dir);
    }
}

PHP:

public function delete_files($target) {
        if(is_dir($target)){
            $files = glob( $target . '*', GLOB_MARK ); //GLOB_MARK adds a slash to directories returned

            foreach( $files as $file )
            {
                $this->delete_files( $file );
            }

            rmdir( $target );
        } elseif(is_file($target)) {
            unlink( $target );
        }
    }

Please help, idk what I do wrong...

 

Solved with SkyZoneMC in a private discord chat.
He was missing $this->dir = $dir; in his task constructor.

PHP:

public function __construct(CWTraining $plugin, string $dir) {
    $this->plugin = $plugin;
}