code: def add_hierarchy(self, parent, edge, child):  # XXX DEPRECATED
          
          if type(parent) != rdflib.URIRef:
              parent = self.check_thing(parent)
  
          if type(edge) != rdflib.URIRef:
              edge = self.check_thing(edge)
  
          if type(child) != infixowl.Class:
              if type(child) != rdflib.URIRef:
                  child = self.check_thing(child)
              child = infixowl.Class(child, graph=self.g)
  
          restriction = infixowl.Restriction(edge, graph=self.g, someValuesFrom=parent)
          child.subClassOf = [restriction] + [c for c in child.subClassOf]
docs: Helper function to simplify the addition of part_of style
              objectProperties to graphs. FIXME make a method of makeGraph?