title: get the last sunday and saturday's date in python
body: <p>Looking to leverage <code>datetime</code> to get the date of beginning and end of the previous week, sunday to saturday.</p>
  
  <p>So, if it's 8/12/13 today, I want to define a function that prints:</p>
  
  <p><code>Last Sunday was 8/4/2013 and last Saturday was 8/10/2013</code></p>
  
  <p>How do I go about writing this?</p>
  
  <p>EDIT: okay, so there seems to be some question about edge cases. For saturdays, I want the same week, for anything else, I'd like the calendar week immediately preceding <code>today</code>'s date.</p>