Help me out (Im new to developing PM plugins - erros in my code)

PHP:

<?php

namespace Hello;

use pocketmine\plugin\PluginBase;
use pocketmine\command\Command;
use pocketmine\command\CommandSender;

class Hello extends PluginBase{

    public function onEnable(){
        $this->getLogger()->info("onEnable() has been called!");
    }
 
    public function onLoad(){
     
    }

    public function onDisable(){
        $this->getLogger()->info("onDisable() has been called!");
    }
}



public function onCommand(CommandSender $sender, Command $command, $label, array $args){
    if(strtolower($command->getName()) === "hello"){
        sender->sendMeassage("hello there".sender->getName()"!");
        return true;
    }

    return false;

I apologize for my terrible mistakes, im learning through my mistakes

So

Thanks for the reply i cant test it now :/ anyway what was my mistake, what was the syntax error?

And close braces