Kutu.py

from kivy.app import App
from kivy.uix.gridlayout import GridLayout
from kivy.core.window import Window
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen

Window.clearcolor = .3, .3, .3, 1

class Calculator(GridLayout,Screen):
    def calculate(self, calculation):
        if calculation:
            try:
                self.display.text = str(eval(calculation))
            except Exception:
                self.display.text = "Error"

class MenuScreen(Screen):
    pass

class CalculatorScreen(Screen):
    pass

class SecondScreen(Screen):
	pass

class ScreenManagement(ScreenManager):
    pass

class kutuApp(App):
    def build(self):
        return ScreenManagement()


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