@type t() :: %Polarex.CheckoutLinkUpdate{
  allow_discount_codes: boolean() | nil,
  discount_id: String.t() | nil,
  label: String.t() | nil,
  metadata: map() | nil,
  products: [String.t()] | nil,
  require_billing_address: boolean() | nil,
  return_url: String.t() | nil,
  success_url: String.t() | nil,
  trial_interval: String.t() | nil,
  trial_interval_count: integer() | nil
}