@type t() :: %DocuSign.Model.BillingInvoicesSummary{
  accountBalance: String.t() | nil,
  billingInvoices: [DocuSign.Model.BillingInvoice.t()] | nil,
  currencyCode: String.t() | nil,
  pastDueBalance: String.t() | nil,
  paymentAllowed: String.t() | nil
}