docs: def getClassDirectSubs(self, aURI):
          """
          2015-06-03: currenlty not used, inferred from above
          """
          aURI = aURI
          qres = self.rdfgraph.query(
                """SELECT DISTINCT ?x
                   WHERE {
                       { ?x rdfs:subClassOf <%s> }
                       FILTER (!isBlank(?x))
                   }
                   """ % (aURI))
          return list(qres)