def on_player_join(event):
   print(event.getPlayer().getUniqueId())

def on_test_command(sender, command, label, args):
    sender.sendMessage("success!")
    return True

def on_test_tab(sender, command, label, args):
    if len(args) == 1:
        return ["asd"]
    return []

@events.on_enable
def on_enable():
    events.register(EventType.PLAYER_JOIN_EVENT, on_player_join)
    commands.register("test", on_test_command, on_test_tab)