How to get latest version in Windchill

public static EPMDocument getLatestWTDocument(EPMDocument epmDoc) {
SessionServerHelper.manager.setAccessEnforced(false);
if (epmDoc == null)
return null;
try {
QueryResult qr = VersionControlHelper.service.allVersionsOf(epmDoc.getMaster());
while (qr.hasMoreElements()) {
return (EPMDocument) qr.nextElement();
}
} catch (PersistenceException e) {
e.printStackTrace();
} catch (WTException e) {
e.printStackTrace();
}
return null;
}