code: def _merge_update_item(self, model_item, data):
          
          data_item = self.edit_model_schema.dump(model_item, many=False).data
          for _col in self.edit_columns:
              if _col not in data.keys():
                  data[_col] = data_item[_col]
          return data
docs: Merge a model with a python data structure
              This is useful to turn PUT method into a PATCH also
          :param model_item: SQLA Model
          :param data: python data structure
          :return: python data structure