Выбор Jfreechart

Большое спасибо! Это работает сейчас! Следуйте коду:

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.lang import Builder
import matplotlib.pyplot as plt
import matplotlib
matplotlib.use("module://kivy.garden.matplotlib.backend_kivy")
from kivy.garden.matplotlib import FigureCanvasKivyAgg

from kivy.uix.widget import Widget

plt.plot([1,23,2,4])
plt.ylabel("alguns numeros legais")

class Sensores(Screen):
    pass

class Grafico(Screen):
    def on_enter(self, *args):
        box = BoxLayout()
        box.add_widget(FigureCanvasKivyAgg(plt.gcf()))
        self.add_widget(box)

class Menu(ScreenManager):
    pass

presentation = Builder.load_file('sensor.kv')

class sensor(App):
    def build(self):
        return presentation

if __name__ == "__main__":
    sensor().run()

KV LANG
#:kivy 1.9.1

Menu:
    Sensores:
    Grafico:
        name: 'grafico'

<Sensores>
    name: 'sensores'
    BoxLayout:
        Button:
            text: "Sensor 01"
            on_release:
                root.manager.current = 'grafico'

<Grafico>
    name: 'grafico'