@type t() :: %PolarExpress.Schemas.ProductPriceFixed{
  amount_type: String.t() | nil,
  created_at: DateTime.t() | nil,
  id: String.t() | nil,
  is_archived: boolean() | nil,
  modified_at: DateTime.t() | nil,
  price_amount: integer() | nil,
  price_currency: String.t() | nil,
  product_id: String.t() | nil,
  recurring_interval:
    PolarExpress.Schemas.SubscriptionRecurringInterval.t() | nil,
  source: PolarExpress.Schemas.ProductPriceSource.t() | nil,
  type: PolarExpress.Schemas.ProductPriceType.t() | nil
}