code: def update(self, ns, docid, raw, **kw):
          
          self._dest_coll(ns).update(raw['o2'], raw['o'], safe=True)
docs: Perform a single update operation.
  
              {'docid': ObjectId('4e95ae3616692111bb000001'),
               'ns': u'mydb.tweets',
               'raw': {u'h': -5295451122737468990L,
                       u'ns': u'mydb.tweets',
                       u'o': {u'$set': {u'content': u'Lorem ipsum'}},
                       u'o2': {u'_id': ObjectId('4e95ae3616692111bb000001')},
                       u'op': u'u',
                       u'ts': Timestamp(1318432339, 1)}}