MenuGUI Command Help

Here is my code :
<?php

namespace Menu;

use pocketmine\inventory\transaction\action\SlotChangeAction;
use pocketmine\item\Item;
use pocketmine\Player;
use pocketmine\math\Vector3;
use pocketmine\plugin\PluginBase;
use pocketmine\command\Command;
use pocketmine\command\CommandSender;
use pocketmine\event\Listener;
use muqsit\invmenu\InvMenuHandler;
use muqsit\invmenu\InvMenu;

class Menu{

private $plugin;

public function __Construct(Main $plugin){
$this->plugin = $plugin;
if (!InvMenuHandler::isRegistered()) {
InvMenuHandler::register($plugin);
}

public function onCommand(CommandSender $sender, Command $cmd, string $label,array $args) : bool {
switch($cmd->getName()){
case "menu":
if($sender instanceof Player){
$player = $sender->getName();
$this->Menu($sender);
}else{
$sender->sendMessage("Er.......");
}
return true;
}
}

public function Menu(Player $player){
$menu = InvMenu::create(InvMenu::TYPE_CHEST);
$menu->readonly();
$menu->setName("§l§eGame§b Menu");
//[Murder] Item
$murder = Item::get(378, 0, 1);
$murder->setCustomName("§l§cMur§eder");
$murder->setLore(array("§l§eTap to§a Play"));
//[Player Head] Item
$playerhead = Item::get(144, 0, 1);
$playerhead->setLore(array("§aĐây là thông tin của bạn! Chạm vào để xem§r\n§aTên: $player"));
$playerhead->setCustomName("§l§aI§bn§cf§do");
//Inventory
$inv = $menu->getInventory();
$inv->setItem(6, $playerhead);
$inv->setItem(13, $murder);
$menu->setListener([$this, "onTransaction"]);
$menu->setListener(function(Player $player, item $itemClickedOn, Item $itemClickedwith): bool{
if($itemClickedOn->getCustomName() == "§l§cMur§eder"){
$this->getServer()->getCommandMap()->dispatch($player, "mdui");
}
return true;
});
$menu->send($player);
}

public function onTransaction(Player $player, Item $itemTakenOut, Item $itemPutIn, SlotChangeAction $inventoryAction) : bool{
$player->removeWindow($inventoryAction->getInventory());
return true;
}
}
It didnt show the fake chest when i typed /menu