def METHOD_NAME(
    self,
    cost_category_arn: str,
    effective_start: Optional[str],
    rule_version: str,
    rules: List[Dict[str, Any]],
    default_value: str,
    split_charge_rules: List[Dict[str, Any]],
) -> Tuple[str, str]:
    """
    The EffectiveOn-parameter is not yet implemented
    """
    cost_category = self.describe_cost_category_definition(cost_category_arn)
    cost_category.update(
        rule_version=rule_version,
        rules=rules,
        default_value=default_value,
        split_charge_rules=split_charge_rules,
        effective_start=effective_start,
    )
    return cost_category_arn, cost_category.effective_start