Base Transaction Request
constructor(lineItems: List<PaymentLineItem>, currency: String, merchantReference: String = "", invoiceReference: String? = null, customerId: String? = null, customerEmailAddress: String? = null, billingAddress: PostalAddress? = null, shippingAddress: PostalAddress? = null, metadata: Map<String, String> = emptyMap(), customText: String? = null, language: String? = null, panHashVariants: List<PanHashVariant> = emptyList(), transactionRefNumber: String? = null, showTransactionResultScreens: Boolean? = null)