title: PyQt5 styleSheet Animation
body: <p>I am using PyQt5 to build an app with multiple buttons.
  What I am trying to accomplish is to create a blinking background color (yellow-red) for some of my buttons.</p>
  
  <pre><code>btn1.setStyleSheet("background-color: green; color: red; font-weight: 800; font-size: 22")
  tobyte = 'styleSheet'
  a = bytearray(tobyte, 'utf-8')
  animation = QtCore.QPropertyAnimation(' + 'btn' + str(yy) + ', a)
  animation.setDuration(1000)
  animation.setLoopCount(1000)
  animation.setStartValue("background-color: yellow; color: red; font-weight: 800; font-size: 22")
  animation.setEndValue("background-color: red; color: red; font-weight: 800; font-size: 22")
  animation.start()
  </code></pre>
  
  <p>The animation starts (it removes the predefined, green background), but it doesn't change the background color of the button to yellow or red.</p>
  
  <p>Any ideas?</p>