title: Python datetime to XML Schema timestamp format
body: <p>Is there an easy way to create a timestamp, in XML Schema format?</p>
  
  <p><code>datetime.datetime.now()</code> does not work.</p>
  
  <pre><code>.now(): 2012-02-17 09:52:35.033232
  
  Desired: 2012-02-15T14:18:46.295-02:00
  </code></pre>
  
  <p>Looks pretty much the same, but fails on schema validation.</p>