title: How to insert datetime string into Mongodb as ISODate using pymongo
body: <p>How to insert datetime string like this <code>"2017-10-13T10:53:53.000Z"</code> into mongo db as ISODate? 
  I get a string in mongodb when I insert:
   <code>datetime.strptime("2017-10-13T10:53:53.000Z", "%Y-%m-%dT%H:%M:%S.000Z")</code></p>