KIvy grid height

[Andrei Marin]

hello i want to change the height of the lines so that they are more stuck together, how do i do it

, this is my code:

from kivy.app import App
from kivy.uix.gridlayout import GridLayout
from kivy.uix.label import Label
from kivy.uix.textinput import TextInput
from kivy.clock import Clock

class main_page(GridLayout):



    def __init__(self, **kwargs):

        self.line = 0
        self.ballx= 2
        self.bally= 2
        self.width = 10
        self.aaa=10
        super(main_page, self).__init__(**kwargs)
        self.cols = 1
        self.add_widget(Label(text="hello"))
        Clock.schedule_once(self.my_callback, 1)

    def my_callback(self, dt):
        self.clear_widgets()
        Clock.schedule_once(self.aparitie, .5)

    def aparitie(self, dt):
        for x in range(self.aaa):
            self.line+=1
            if self.line==self.ballx:
                self.add_widget(Label(text="."*(self.bally-1)+"X"+"."*(20-self.bally)))
            else:
                self.add_widget(Label(text="."*20 ))


class MyApp(App):

    def build(self):
        return main_page()


if __name__ == '__main__':
    MyApp().run()