title: Date String to Time tuple
body: <p>I am trying to pass a string into as function and need to convert it into a time tuple:</p>
  <pre><code>def  sim(startdate, enddate):
      # need to convert the date from string to integer time tuple:
      dt_start = dt.date(startdate)
      print 'Start Date: ', dt_start
  
      dt_end = dt.date(enddate)
      print 'End Date: ', dt_end
  
  # in String format
  sim('Jan 1, 2011', 'Dec 31, 2011')
  
  # in interger in string format
  sim('2011,1,1', '2011,12,31')
  </code></pre>