class Reposo(Widget):
    ReposoRoot = GridLayout(cols = 9, rows = 5, padding = 100)
    self.getAnuncios(ReposoRoot)

    def getAnuncios(self, ReposoRoot):
        ReposoRoot.add_widget(Button(text='Hello 1'))

class PanelApp(App):
        def build(self):
                Panel = FloatLayout()
                ReposoWid = Reposo()
                Panel.add_widget(ReposoWid)
                return Panel