@Nonnull
private static OBODoc createPVDoc() {
OBODoc oboDoc = new OBODoc();
Frame headerFrame = new Frame(FrameType.HEADER);
headerFrame
.addClause(new Clause(OboFormatTag.TAG_FORMAT_VERSION, "1.2"));
headerFrame.addClause(new Clause(OboFormatTag.TAG_ONTOLOGY, "test"));
addPropertyValue(headerFrame, "http://purl.org/dc/elements/1.1/title",
"Ontology for Biomedical Investigation", "xsd:string");
addPropertyValue(headerFrame, "defaultLanguage", "en", "xsd:string");
oboDoc.setHeaderFrame(headerFrame);
return oboDoc;