如何用python在kivy语言中更改标签的文本

I was wondering how I could change the text of a label made inside the Kivy language using Python. Like how would I have user input from python be made as the text of a label in kivy. (By the way I have the formatting correct in the actual program but I screwed up pasting it to stackoverflow) Say if I wanted to make the text of the label in from the code be a random number generated in python how would I go about doing that?I was wondering how I could change the text of