title: Difference between __getattr__ and __getattribute__
body: <p>I am trying to understand when to define <code>__getattr__</code> or <code>__getattribute__</code>.  The <a href="http://docs.python.org/reference/datamodel.html?highlight=__getattribute__#object.__getattribute__" rel="noreferrer">python documentation</a> mentions <code>__getattribute__</code> applies to new-style classes. What are new-style classes?</p>