_:nef3689f1f313459194c8bcbe1de060ffxb3
<http://schema.org/valueRequired>
"true"^^<http://www.w3.org/2001/XMLSchema#boolean>
<https://freecoursesandbooks.net/tag/%D9%83%D9%88%D8%B1%D8%B3-%D8%A8%D8%A7%D9%88%D8%B1-%D8%A7%D9%86%D8%AC%D9%84%D8%B4/>