AttributeError: 'unicode' object has no attribute 'to_etree'
  File "amqp/handler.py", line 66, in wrapper
    f(self=self, parsed_message=parsed_message)
  File "amqp/handler.py", line 172, in index_callback
    data = [entity.query_result_to_dict(obj) for obj in query.all()]
  File "schema/searchentities.py", line 259, in query_result_to_dict
    data["_store"] = tostring(self.compatconverter(obj).to_etree())
  File "mbrng/models.py", line 2760, in to_etree
    status_.to_etree(element, name_='status', mapping_=mapping_)