+ static @Nullable ContainerNode unmaskContainer(final Optional<NormalizedNode> optNode)
+ throws InvalidObjectException {
+ if (optNode.isEmpty()) {
+ return null;
+ }
+ final var node = optNode.orElseThrow();
+ if (node instanceof ContainerNode container) {
+ return container;
+ }
+ throw new InvalidObjectException("Unexpected data " + node.contract().getSimpleName());
+ }
+