I can press a button only once in KIVY

Question

I´m making a kivy program and I have a button which when it´s pressed a label with a number increseas in 1 but for some reason i can only call the function once. Here is my code:

import kivy
kivy.require("1.11.1")

from kivy.app import App
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.button import Button

class Contenedor(FloatLayout):
    def __init__(self):
        super(Contenedor, self).__init__()
        self.sumarHora = Button(text = "h", size_hint = (0.15, 0.15), pos_hint = {'x': 0.33, 'y': .775}, on_press = self.masHora)
        self.hora = Button(text = "0", size_hint = (0.15, 0.25), pos_hint = {'x': 0.33, 'y': .475})
       self.add_widget(self.sumarHora)
       self.add_widget(self.hora)

    def masHora(self, event):
        hora = int(self.hora.text)
        hora =+1
        if hora >= 24:
            hora = 0
        self.hora.text = str(hora)

class MainApp(App):
    title = "Interfaz Grafica"
    def build(self):
        return Contenedor()

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

Answer 1

There's a typo in the code:

hora =+1   # hora = 1

should be replaced with

hora += 1