title: Changing logging's 'basicConfig' which is already set
body: <p>I am using the logging module in python as: </p>
  
  <pre><code>import logging, sys
  logger= logging.getLogger(__file__)
  logging.basicConfig(stream = sys.stderr, level=logging.DEBUG, format='%(filename)s:%(lineno)s %(levelname)s:%(message)s')
  logger.debug("Hello World")
  </code></pre>
  
  <p>Now, after I have set the basic configuration on <code>line 3</code>, I want to have a command line argument that can change the output stream from sys.stderr to a file.</p>
  
  <p>I have read the doc and it says that if both <code>filename</code> and <code>stream</code> are present at the same time, the <code>stream</code> is ignored. </p>
  
  <p>Now, I wanna know how do change the stream to a file after I have already done the <code>basicConfig</code> thing in <code>line 3</code>?</p>