title: Qtreewidget item change color to Icon in Qtreewidgetitem
body: <p>how change background icon inside a qtreewidgetitem dinamically:
  Some code example..</p>
  
  <pre><code>if item.text(0)=="INL"
     item.icon(0).setBackground(Qt.green)
  else:
     item.icon(0).setBackground(Qt.yellow) 
  </code></pre>
  
  <p>I want only icon background not all item (icon+text)..
  <a href="https://i.stack.imgur.com/pgvA4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/pgvA4.png" alt="test"></a></p>