title: subclassing from OrderedDict and defaultdict
body: <p>Raymond Hettinger <a href="http://rhettinger.wordpress.com/2011/05/26/super-considered-super/" rel="nofollow noreferrer">showed</a> a really cool way to combine collection classes:</p>
  
  <pre><code>from collections import Counter, OrderedDict
  class OrderedCounter(Counter, OrderedDict):
    pass
  # if pickle support is desired, see original post
  </code></pre>
  
  <p>I want to do something similar for OrderedDict and defaultdict. But of course, defaultdict has a different <code>__init__</code> signature, so it requires extra work. What's the cleanest way to solve this problem? I use Python 3.3.</p>
  
  <p>I found a good solution here: <a href="https://stackoverflow.com/a/4127426/336527">https://stackoverflow.com/a/4127426/336527</a>, but I was thinking maybe deriving from defaultdict might make this even simpler?</p>