title: How to update a document using elasticsearch-py?
body: <p>Does anyone have an example for how to use update?  It's documented <a href="http://elasticsearch-py.readthedocs.org/en/master/api.html#elasticsearch.Elasticsearch.update" rel="noreferrer">here</a>, but the documentation is unclear and doesn't include a working example.  I've tried the following:</p>
  
  <pre><code>coll = Elasticsearch()
  coll.update(index='stories-test',doc_type='news',id=hit.meta.id,
                  body={"stanford": 1, "parsed_sents": parsed })
  </code></pre>
  
  <p>and I get </p>
  
  <pre><code>elasticsearch.exceptions.RequestError: 
  TransportError(400, u'ActionRequestValidationException[Validation Failed: 1: script or doc is missing;]')
  </code></pre>
  
  <p>I would like to update using a partial doc, but the update method doesn't take any argument named 'doc' or 'document'.</p>