OptionalamountType?: "FORM_ELEMENT"Amount is taken from a form element value.
The elementId that holds the value that will be paid. Must be the id of a number or calculation element.
Amount is a fixed number.
A fixed amount that will be paid.
Amount is calculated from an expression.
The calculation algorithm that must return a number. Supports the same syntax as calculation form elements.
Determines the amount to be paid for a payment event. Exactly one of
elementId,paymentAmount, orpaymentCalculationmust be provided.