title: Unix Time difference to display delay
body: <p>I am using two timestamps to determine delay in djnago project in views.py file :</p>
  
  <pre><code>    import datetime
      import dateutil.relativedelta
  
      def get_diff(url, header) :
         enc_data = utils.http_response('get', url, header)['body']
         json_data =  json.loads(enc_data)['data'] 
         timestamp =  json_data[0]["timestamp"].split('.')[0].split("T")
         lastModified =  json_data[0]["lastModified"].split('.')[0].split("T")
         timestamp = timestamp[0]+ ":" + timestamp[1]
         lastModified = lastModified[0]  + ":" +lastModified[1]
         print json_data[0]
         print timestamp , lastmodified
         diff = dateutil.relativedelta.relativedelta(lastModified, timestamp)
         return diff
  </code></pre>
  
  <p>This is giving error on terminal : </p>
  
  <pre><code>{u'applicationName': u'None', u'userName': u'LocalHardcodedUser', u'facilityId': None, u'resource': u'pat', u'parameters': {u'limit': u'10', u'name': u'sdgds'}, u'accessToken': u'6FDG-TR08', u'lastModified': u'2013-09-26T02:59:14.436562',
  u'uri': u'/v1/pat/519b/clinical', u'method': u'GET', u'requestBody': u'', u'visitNumber': None, u'mr': None, u'timestamp': u'2013-09-25T11:48:01.074000', u'message': u'name', u'rrt': None, u'type': u'error', u'id', u'5242cd71c83', u'statusCode': 500}
  2013-09-25:11:48:01 2013-09-26:02:40:03    #output of **print timestamp , lastmodified**
  Internal Server Error: /v1/ready
  Traceback (most recent call last):
    File "/home/arya/.virtualenv/Devel/.virtualenvs/hu/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 115, in get_response
      response = callback(request, *callback_args, **callback_kwargs)
    File "/home/arya/apps/hma/views.py", line 538, in get_health_check
      diff=  get_diff
    File "/home/arya/apps/hma/views.py", line 531, in get_diff
      print dateutil.relativedelta.relativedelta(lastModified, timestamp)
    File "/home/arya/.virtualenv/Devel/.virtualenvs/hu/local/lib/python2.7/site-packages/dateutil/relativedelta.py", line 118, in __init__
      raise TypeError("relativedelta only diffs datetime/date")
  TypeError: relativedelta only diffs datetime/date
  </code></pre>
  
  <p>Please any one explain correct format that relativedelta accepts.</p>