title: Issue using itemgetter on a nested list of dictionaries
body: <p>I am trying to arrange this nested list in ascending order by special number. I have tried using itemgetter but I received a typerror. Not too sure what the solution is here. thank you!</p>
  <pre><code>from operator import itemgetter
  
  nested = [
     [{'time': 5, 'ask price': 8}, {'ID': 'AA', 'Special number': 0.1}], 
     [{'time': 5, 'ask price': 8}, {'ID': 'BB', 'Special number': 0.15}],
     [{'time': 5, 'ask price': 8}, {'ID': 'CC', 'Special number': 0.05}]
  ]
  
  print(nested.sort(key=itemgetter('Special number'))) 
  </code></pre>
  <p>The error:</p>
  <pre><code>TypeError: list indices must be integers or slices, not str
  </code></pre>