title: DynamoDB insert (put) item - return the item created?
body: <p>In my Python script I insert a record (item) into DynamoDB table, but I realized the response from AWS doesn't include the actual item inserted:</p>
  
  <pre><code>{'ResponseMetadata': {'HTTPHeaders': {'connection': 'keep-alive',
     'content-length': '2',
     'content-type': 'application/x-amz-json-1.0',
     'date': 'Fri, 27 Jan 2017 23:31:22 GMT',
     'server': 'Server',
     'x-amz-crc32': '234324243',
     'x-amzn-requestid': 'xxxxxxxxxx'},
    'HTTPStatusCode': 200,
    'RequestId': 'xxxxxxxxxx',
    'RetryAttempts': 0}}
  </code></pre>
  
  <p>This is unfortunate as I have logic like:</p>
  
  <pre><code>if not user.exists():
      user = create_user()
  else:
      user = get_user()
  
  user.do_something()
  </code></pre>
  
  <p>and I'd rather not do another round trip just to get the user object I just inserted. </p>
  
  <p>I can, of course, mock the object since using <code>boto3</code> in Python the <code>user</code> object is just a dictionary-like thing, but it's nice to be able to just use a single representation. Also it seems like the <code>put_item</code> call </p>
  
  <pre><code>r = user_table.put_item(Item={'user_id': uid, 'info' : { ... }})
  </code></pre>
  
  <p>should be able to return the put'd item? Or some other endpoint can?</p>
  
  <p>Thanks for any insight!</p>