code: def alreadyHasEntry(oldClassString, og):
      
      namespace = oldClassString.split(':')[0]
      if namespace == 'http':
          target = rdflib.URIRef(oldClassString)
          print('OLD CLASS ID IS A URL', oldClassString)
      else:
          try:
              og.add_known_namespaces(namespace)
              target = og.expand(oldClassString)
          except KeyError:
              print('MISSING NAMESPACE', namespace, oldClassString)
              return True  # we only want known namespaces
      return (target, rdf.type, owl.Class) in og.g
docs: Return true if there is already an owl:Class with the old id