I have a problem with my kivy app. Help me please.

Question

my application, when clicking on the button "the next player should make the next button green, the current button (which is now green) should be gray. This does not happen. Can you explain why this happens and correct the error please

Answer 1

I dont see nobody

Answer 2

What do you mean by that

Answer 3

https://code.sololearn.com/cGcbZH5qQQay/?ref=app