I have a question for developing a plugin

Um.. I have a question..
how to use a pocketmine\command\CommandMap::register(); ...
Please give me to do that...

PHP:

namespace your\name\space;
use pocketmine\command as cmd;

class MyCommand extends cmd\Command implements cmd\PluginIdentifiableCommand{
  private $plugin;
  public function __construct(MainClass $plugin){
    parent::__construct("cmdname", "description", "usage", ["aliases"]);
    $this->setPermission("your.command.permission.node");
    $this->plugin = $plugin;
  }
  public function getPlugin(){
    return $this->plugin;
  }
  public function execute(cmd\CommandSender $sender, $label, array $args){
    // your code here
  }
}


PHP:

namespace your\name\space;
use pocketmine\plugin\PluginBase;

class MainClass extends PluginBase{
  public function onEnable(){
    $this->getServer()->getCommandMap()->register(new MyCommand($this));
  }
}

Thank you, sir!