calculation

record calculation {
  amount-total: s32,
  currency: string,
  customer: option​<string>,
  customer-details: product-resource-customer-details,
  expires-at: option​<s32>,
  id: option​<string>,
  line-items: option​<calculation-line-items>,
  livemode: bool,
  object: calculation-object-enum,
  shipping-cost: option​<string>,
  tax-amount-exclusive: s32,
  tax-amount-inclusive: s32,
  tax-breakdown: list​<product-resource-tax-breakdown>,
  tax-date: s32,
}