title: __repr__ for Exception derived class not works well
body: <p>I tried to use <code>__repr__</code> method on object that inherit from Exception.</p>
  
  <p>but nothing was printed!</p>
  
  <p>Can anyone help explain why?</p>
  
  <pre><code>class MyException(Exception):
      def __repr__(self):
          return "MyException Object"
  
  
  try:
      raise MyException()
  except MyException as e:
      print(e)   # shows nothing!
  </code></pre>