How to change label on button click in .kv file?

Question

Python

How to make it so that when the button is pressed, 1 of the two labels changes its text?
At the same time, label and button in .kv file

Answer 1

Declare variables at the class level and give them the ObjectProperty (None) property for all widgets, then write a color change method through the function, and in the kv file give the command to the button