title: How can I create kv file?
body: <p>I read 'Creating Apps in Kivy'. And there is the code like below.</p>
  
  <pre><code>from kivy.app import App
  
  App().run()
  
  
  class WeatherApp(App):
      pass
  
  if __name__ == '__main__':
      WeatherApp().run()
  </code></pre>
  
  <p>After finishing above code, the Book said you create kv file in the same directory as main.py.
  But I don't how to create kv file.
  How??
  help me~~</p>