List<Node> parentsRequiredToBeExclusive() {
        return nodes.values()
                    .stream()
                    .filter(candidate -> candidate.exclusiveParent)
                    .map(candidate -> candidate.parent.orElseThrow())
                    .toList();
    }
The node type this is allocating
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/NodeAllocation.java