originSignaturePayload method Null safety

Uint8List originSignaturePayload()

Implementation

Uint8List originSignaturePayload() {
  final Uint8List payloadForPreviousSignature = previousSignaturePayload();
  return concatUint8List([
    payloadForPreviousSignature,
    previousPublicKey!,
    Uint8List.fromList([previousSignature!.length]),
    previousSignature!,
  ]);
}