title: datetime TypeError: not all arguments converted during string formatting
body: <p>I am sure there are easier ways to do this, but I am not sure why I keep getting a TypeError.</p>
  
  <pre><code>   import datetime
     getdate = datetime.date.today()
     thirty = datetime.timedelta(days=30)
     last_month = getdate - thirty
     print json.dumps(api.get_zone_stats(3, "daily", "%s", "%s" %(last_month, getdate)))
  </code></pre>
  
  <p>Traceback (most recent call last):
  ...</p>
  
  <p><strong>TypeError: not all arguments converted during string formatting</strong></p>