How To: Clear Screen Funktion

<?php
namespace chat\system\command\commands;
use \wcf\system\WCF;


/**
 * Clears the chat. Don't use it to troll
 */
class ClsCommand extends \chat\system\command\AbstractRestrictedCommand {

    /**
     * @see    \chat\system\command\IRestrictedCommand::checkPermission()
     */
    public function checkPermission() {
        parent::checkPermission();

        WCF::getSession()->checkPermissions(array('user.chat.canTempRoom')); //change to mod.chat.canClearScreen
    }    

    /**
     * @see    \chat\system\command\ICommand::getType()
     */
    public function getType() {
        return \chat\data\message\Message::TYPE_CLEAR;
    }

    /**
     * @see    \chat\system\command\ICommand::getMessage()
     */
    public function getMessage() {
        return "Der Chatverlauf wurde geleert! Oh noez!";
    }
}