code: def get_values_json(self, lst, list_columns):
          
          result = []
          for item in self.get_values(lst, list_columns):
              for key, value in list(item.items()):
                  if isinstance(value, datetime.datetime) or isinstance(
                      value, datetime.date
                  ):
                      value = value.isoformat()
                      item[key] = value
                  if isinstance(value, list):
                      item[key] = [str(v) for v in value]
              result.append(item)
          return result
docs: Converts list of objects from query to JSON