title: python multiprocessing pickle protocol
body: <p>I am using the Python multiprocessing module to place objects onto a queue and have them processed by several workers.  My first issue was getting bound instance methods to pickle, which I have working, but now I'm running into a separate issue caused by the fact that the objects are using <code>__slots__</code>. </p>
  
  <p>When the mp module goes to pickle the objects, it seems to be using the older ascii pickle protocol, that can't handle <code>__slots__</code>.  The newer protocol does handle this, but I'm not sure how to make the mp module use this protocol.</p>
  
  <p>Anyone have any experience with this?</p>