title: logging exceptions in Python 3
body: <p>I have the following :</p>
  
  <pre><code>### running with Python 3 
  import logging 
  logger = logging.getLogger(__name__)                                                                                                              
  logger.setLevel('DEBUG')                                                                           
  logger.exception('this is an exception')                                  
  </code></pre>
  
  <p>The output is:</p>
  
  <pre><code>this is an exception
  NoneType: None
  </code></pre>
  
  <p>What do i need to do to get rid of that "NoneType: None" output?</p>