code: def one(self):
          
          results = self.rpc_model.search_read(
              self.domain, 2, None, self._order_by, self.fields,
              context=self.context
          )
          if not results:
              raise fulfil_client.exc.NoResultFound
          if len(results) > 1:
              raise fulfil_client.exc.MultipleResultsFound
          return results[0]
docs: Return exactly one result or raise an exception.
  
          Raises fulfil_client.exc.NoResultFound if the query selects no rows.
          Raises fulfil_client.exc.MultipleResultsFound if multiple rows are
          found.