docs: def delete(self, ns, docid, raw, **kw):
          """ Perform a single delete operation.
  
              {'docid': ObjectId('4e959ea11669210edc002902'),
               'ns': u'mydb.tweets',
               'raw': {u'b': True,
                       u'h': -8347418295715732480L,
                       u'ns': u'mydb.tweets',
                       u'o': {u'_id': ObjectId('4e959ea11669210edc002902')},
                       u'op': u'd',
                       u'ts': Timestamp(1318432261, 10499)}}
          """
          self._dest_coll(ns).remove(raw['o'], safe=True)