local files in kivy

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.button import Button
from kivy.properties import ObjectProperty
from kivy.uix.gridlayout import GridLayout

import fiona
import sqlite3




class AddButton(Button):
    pass


class SubtractButton(Button):
    pass


class Container(GridLayout):
    display = ObjectProperty()

    def add_one(self):

    value = int(self.display.text)
        conn = sqlite3.connect('./test.sqlite')
    cur = conn.cursor()
    cur.execute("select 1 as a")
    self.display.text=str(cur.fetchone()["a"])

    def subtract_one(self):
        value = int(self.display.text)
    peo=fiona.open('./etiquetas_geo.shp')

        self.display.text = str(value-1)


class MainApp(App):
    def build(self):
    self.title = 'Probatina'
        return Container()


if __name__ == "__main__":
    app = MainApp()
    app.run()