@type t() :: %Polarex.OrderCreate{
  amount: integer() | nil,
  currency: String.t() | nil,
  custom_field_data: map() | nil,
  customer_id: String.t(),
  description: String.t() | nil,
  metadata: map() | nil,
  organization_id: String.t() | nil,
  product_id: String.t()
}