How to set up Label in python kivy?

Question

Kivy

I wrote label:

self.TextDEFS = Label(text = "Functions:\n", color=(.9,.9,.9, 1), font_size='15sp', size_hint = (.1, .1), pos_hint = {'center_x': 0.93, 'center_y': 0.86})

my code is written so that when you click on the button to the current text in the Label, the text is added from a new line:
https://www.youtube.com/watch?v=fT5usm-4zBQ&ab_cha...

as you can see in the video, if you add a lot text, Label will fit on top of the button, how to make the text go only down?