Short kivy file creates pygame segfault

gistfile1.txt

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
kv = '''
<MainUI>:
  BoxLayout:
		Button: 
			text: 'Hello'
'''
class MainUI(Button):
	pass

class MahApp(App):
	def build(self):
		return MainUI
		
if __name__ == '__main__':
    MahApp().run()

Leads to Fatal Python error: (pygame parachute) Segmentation Fault