Help undifined offset 1

[11:00:40] [Server thread/CRITICAL]: ErrorException: "Undefined offset: 1" (EXCEPTION) in "plugins/KartAPI/src/leinne/plugin/kartapi/command/KartCommand" at line 34

Code:

PHP:

public function execute(CommandSender $sender, string $commandLabel, array $args) : void{
        if(!$sender instanceof Player || !$this->testPermission($sender)){
            return;
        }
            if(!isset($args[0])) {
            $sender->sendMessage("§r§l§b[Automotive Core]§r§f How to use: /$commandLabel <buy|sell>[<name>]");
            return;
        }
        switch ($args[0]) { 
            case "buy":
                $kart = KartAPI::getInstance()->getKart($args[1]);
                if($kart === null){
                    $sender->sendMessage("§r§l§b[Automotive Core]§r§f It doesn't exist..");
                    return;
                }
                KartAPI::getInstance()->buyKart($sender, $kart);
                break;
            case "sell":
                KartAPI::getInstance()->sellKart($sender);
                break;
        }
    }

}

 

public function execute(CommandSender $sender, string $commandLabel, array $args) : void{
if(!$sender instanceof Player || !$this->testPermission($sender)){
return;
}
if(!isset($args[0])) {
$sender->sendMessage("§r§l§b[Automotive Core]§r§f How to use: /$commandLabel <buy|sell>[<name>]");
return;
}
switch ($args[0]) {
case "buy":
if(!isset($args[1])){
$sender->sendMessage("/$commandLabel buy <name>");
return;
}
$kart = KartAPI::getInstance()->getKart($args[1]);
if($kart === null){
$sender->sendMessage("§r§l§b[Automotive Core]§r§f It doesn't exist..");
return;
}
KartAPI::getInstance()->buyKart($sender, $kart);
break;
case "sell":
KartAPI::getInstance()->sellKart($sender);
break;
}
}

 

Change

PHP:

if(!isset($args[0])) {

to

PHP:

if(!isset($args[1])) {