@type t() ::
  %Stripe.Params.InvoiceCreatePreviewParams.ScheduleDetails.Phases.AddInvoiceItems{
    discounts:
      [
        Stripe.Params.InvoiceCreatePreviewParams.ScheduleDetails.Phases.AddInvoiceItems.Discounts.t()
      ]
      | nil,
    metadata: %{required(String.t()) => String.t()} | nil,
    period:
      Stripe.Params.InvoiceCreatePreviewParams.ScheduleDetails.Phases.AddInvoiceItems.Period.t()
      | nil,
    price: String.t() | nil,
    price_data:
      Stripe.Params.InvoiceCreatePreviewParams.ScheduleDetails.Phases.AddInvoiceItems.PriceData.t()
      | nil,
    quantity: integer() | nil,
    tax_rates: map() | nil
  }