title: Kivy: Use a toggle button to change the state of another toggle button
body: <p>For example, in Kivy language:</p>
  
  <pre><code>&lt;MainToggle@ToggleButton&gt;:
      on_state: # something that will change the state of the sub-toggle
  
  &lt;SubToggle@ToggleButton&gt;:
      on_state: self.background_color = 0,0,0,1 # the sub-toggle button changes color 
  </code></pre>