get
Retrieves the idempotency key used in the payment request associated with the given paymentAttemptId, if the paymentAttemptId was used in the last 24 hours. The returned idempotency key can be used to a cancel a payment via the Square Payments API: https://developer.squareup.com/reference/square/payments-api/cancel-payment-by-idempotency-key
Return
the idempotency key associated with the paymentAttemptId, null if not found, or an error if the merchant is not authorized.
Parameters
payment
the unique identifier for the payment attempt.