SessionFixedAmount constructor
      const
      SessionFixedAmount({ 
    
- required int amount,
- required String currency,
- Map<String, SessionCurrencyOptionsValue> ? currencyOptions,
fixed_amount
Describes a fixed amount to charge for shipping. Must be present if type is `fixed_amount`.
Implementation
const SessionFixedAmount({
  required this.amount,
  required this.currency,
  this.currencyOptions,
});