title: AttributeError: 'list' object has no attribute 'values'
body: <p>I have a mistake that I can't solve.. have you got an advice?</p>
  
  <pre><code>polygons = [r['shape_attributes'] for r in a['regions'].values()]
  </code></pre>
  
  <blockquote>
    <p>AttributeError: 'list' object has no attribute 'values'</p>
  </blockquote>