from kivy.app import App
from kivy.uix.widget import Widget
from kivy.properties import ObjectProperty
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen

class PierwszyEkran(Screen):
    pass
class DrugiEkran(Screen):
    pass
class TrzeciEkran(Screen):
    pass
class WindowManager(ScreenManager):
    pass
kv=Builder.load_file('ekrany.kv')

class MojaApp(App):
    def build(self):
        return kv
MojaApp().run()