okay, thanks to you all :)
the method of zamoht works but the one by danpost not?
so here is the error message:
error: method removeObject cannot be applied to given types;
i am a little bit unable so i donĀ“t get her how to post a picture of my library. :D
![Twitter](/assets/twitter-4e19209ef84344ee0c433f4c7bad8d49.png)
![Twitter.hover](/assets/twitter.hover-1fb19a5bafc50deace8f88eaec867845.png)