title: Deep copy of a derived python object
body: <p>I have an object in python that is derived from <code>QtGui.QGraphicsPixmapItem</code> with a few basic attributes and methods. After calling <code>deepcopy</code> on a reference to this object, I get an error saying that <code>underlying C/C++ object has been deleted</code> when I try to use the copy. I had received this error before, and it occured when I didn't call the base class' constructor in <code>__init__</code> so I assume this error is because the <code>QtGui.QGraphicsPixmapItem</code> is not being copied.</p>
  
  <p>How do I go about specifying this? All I know is that there is a <code>__deepcopy__</code> method for this purpose.</p>