public List<NodeType> getAllParents(NodeType node) {
        createNodeIfNotExists(node);

        return parentsOfNode.get(node);
    }
Try to register a new inheritance relationship such that
childNode inherits from parentNode

@return boolean indicating success. Inheritance is unsuccessful if the relationship would create a cycle 
in the inheritance graph.
integration/schema-language-server/language-server/src/main/java/ai/vespa/schemals/index/InheritanceGraph.java