Why not working Health

when Player joins, Player's Health and MaxHealth have to be a value what I reported(reported by PlayerQuitEvent) in yaml. Reporting works well, but I think here has a problem. No error but not working. what's wrong? when I join, the MaxHealth and Health changes to 20.

PHP:

function Join(PlayerJoinEvent $event){

    $Players = $event->getPlayer()->getName();

if ( isset($MaxHealth) && isset($Health) ){

    $MaxHealth = $this->GO["MaxHealth"]["$Players"];

    $Health = $this->GO["Health"]["$Players"];

    $event->getPlayer()->setMaxHealth($MaxHealth);

    $event->getPlayer()->setHealth($Health);

}

}

 

PHP:

public function Join(PlayerJoinEvent $event){

    $Players = $event->getPlayer()->getName();
    $MaxHealth = $this->GO["MaxHealth"]["$Players"];
    $Health = $this->GO["Health"]["$Players"];

    if (!isset($MaxHealth) && !isset($Health) ){
        $event->getPlayer()->setMaxHealth($MaxHealth);
        $event->getPlayer()->setHealth($Health);
    }
}

Try this if you're still having errors