from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.lang.builder import Builder
from kivy.properties import ObjectProperty

Builder.load_string('''
<textable_widget>:
	orientation: 'vertical'
		
	Label:
		id: var_label
		text: 'Variable text'
''')

class textable_widget(BoxLayout):	
	pass

class textable_classApp(App):	
		
	def build(self):
		
		return textable_widget()

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