@type t() :: %PolarExpress.Schemas.SubscriptionCanceledMetadata{
  amount: integer() | nil,
  cancel_at_period_end: boolean() | nil,
  canceled_at: String.t() | nil,
  currency: String.t() | nil,
  customer_cancellation_comment: String.t() | nil,
  customer_cancellation_reason: String.t() | nil,
  ends_at: String.t() | nil,
  product_id: String.t() | nil,
  recurring_interval: String.t() | nil,
  recurring_interval_count: integer() | nil,
  subscription_id: String.t() | nil
}