@type t() :: %Paypal.Subscription.BillingInfo{
  cycle_executions: [map()] | nil,
  failed_payments_count: integer() | nil,
  final_payment_time: DateTime.t() | nil,
  last_payment: map() | nil,
  next_billing_time: DateTime.t() | nil,
  outstanding_balance: Paypal.Common.CurrencyValue.t() | nil
}

Subscription billing info:

• outstanding_balance - Monetary amount currently owed.
• cycle_executions - List of executed billing cycle details.
• last_payment - Last payment info including amount and date.
• next_billing_time - Date and time for next scheduled payment.
• final_payment_time - Date and time for final payment if applicable.
• failed_payments_count - Number of consecutive failed payment attempts.