code: def predicates(self) -> Dict[str, URIRef]:
          
          rval = dict()
          for parent in self._o.objects(self._subj, RDFS.subClassOf):
              if isinstance(parent, URIRef) and not str(parent).startswith(str(W5)):
                  rval.update(**FHIRMetaVocEntry(self._o, parent).predicates())
          for s in self._o.subjects(RDFS.domain, self._subj):
              rval[self._to_str(s)] = s
          return rval
docs: Return the tag names and corresponding URI's for all properties that can be associated with subject
          :return: Map from tag name (JSON object identifier) to corresponding URI