public static Uri GetVersionUri(this Ontology ontology) { if (!ontology.HasVersionUri()) { throw new RdfException($"Ontology {ontology} does not have an owl:versionIRI annotation"); } IUriNode versionIri = ontology.Graph.CreateUriNode(VocabularyHelper.OWL.versionIRI); return(ontology.GetNodesViaPredicate(versionIri).UriNodes().First().Uri); }