code: def update(self, resource_id, data=None, **params):
          
          path = self.get_resource_name() + '/' + str(resource_id)
          result = self.perform_api_call(self.REST_UPDATE, path, data=data)
  
          for line in result['lines']:
              if line['id'] == resource_id:
                  return self.get_resource_object(line)
          raise DataConsistencyError('Line id {resource_id} not found in response.'.format(resource_id=resource_id))
docs: Custom handling for updating orderlines.
  
          The API returns an Order object. Since we are sending the request through an orderline object, it makes more
          sense to convert the returned object to to the updated orderline object.
  
          If you wish to retrieve the order object, you can do so by using the order_id property of the orderline.