Crash with Plugin

I edited Minifixio's 1vs1 Plug 'cause everyone can reference a arena. But now I get some syntax error

Code:

[Server] Parse error: syntax error, unexpected ':', expecting ',' or ';' in /storage/sdcard0/PocketMine/plugins/§lHydraPvP§r/src/Minifixio/onevsone/command/JoinCommand.php on line 21
[Server] [20:05:56] [Server thread/EMERGENCY]: Ein nicht-behebbarer Fehler ist aufgetreten und der Server stürzte ab. Erstelle einen Crash-Dump...

So, heres the error file (I get an error with the ':' after the command name )

Code:

<?php

namespace Minifixio\onevsone\command;

use pocketmine\command\Command;
use pocketmine\command\PluginIdentifiableCommand;
use pocketmine\command\CommandSender;
use pocketmine\level\Level;
use pocketmine\Player;
use pocketmine\Server;
use pocketmine\utils\TextFormat;


use Minifixio\onevsone\OneVsOne;
use Minifixio\onevsone\ArenaManager;

class JoinCommand extends Command implements PluginIdentifiableCommand{

    private $plugin;
    private $arenaManager;
    public $commandName = "pvp":

if($sender instanceof Player){
                        if($sender->hasPermission("hydrapvp.join")){
                            $this->plugin->JoinCommand($sender);
                            return true;
                        }else{
                            $sender->sendMessage($this->plugin->translateColors("&", "&cYou don't have permissions to use this command"));
                            return true;
                        }

    public function __construct(OneVsOne $plugin, ArenaManager $arenaManager){
        parent::__construct($this->commandName, "Betrete die Warteschlange für HydraPvP!");
        $this->setUsage("/$this->commandName");
       
        $this->plugin = $plugin;
        $this->arenaManager = $arenaManager;
    }

    public function getPlugin(){
        return $this->plugin;
    }

    public function execute(CommandSender $sender, $label, array $params){
        if(!$this->plugin->isEnabled()){
            return false;
        }

        if(!$sender instanceof Player){
            $sender->sendMessage("Please use the command in-game");
            return true;
        }
       
        $this->arenaManager->addNewPlayerToQueue($sender);
       
        return true;
    }
}