title: How can I find week numbers with weeks starting on Sunday in Python?
body: <p>Total newbie to Python, so apologies in advance if this is obvious. I have a number of datetime values, for which I would like to identify a year and week number, for example:</p>
  
  <pre><code>start_date = datetime.datetime(2015,1,26,0,0,0)
  </code></pre>
  
  <p>The catch is, I would like the week to be defined as starting on a Sunday.</p>
  
  <p>I understand that the datetime.isocalendar() can get me week numbers, but they will be calculated under the assumption that weeks start on Mondays. Is there any other way?</p>
  
  <p>Edit: Running Python 2.7.6</p>
  
  <p>Thank you!</p>