code: def _limit_is_valid_or_none(self, params):
          
          if not "limit" in params or not params["limit"]:
              return True
          if not isinstance(params["limit"], int) or params["limit"] < 1:
              return False
          if not "order_by" in params:
              return False
          return True
docs: Validates that a given limit is not present or is well-formed.
  
          :param params: Query params.
          :return: Returns True if a limit is present or is well-formed.