code: def detect_namespace(rdf):
      
  
      # pick a concept
      conc = rdf.value(None, RDF.type, SKOS.Concept, any=True)
      if conc is None:
          logging.critical(
              "Namespace auto-detection failed. "
              "Set namespace using the --namespace option.")
          sys.exit(1)
  
      ln = localname(conc)
      ns = URIRef(conc.replace(ln, ''))
      if ns.strip() == '':
          logging.critical(
              "Namespace auto-detection failed. "
              "Set namespace using the --namespace option.")
          sys.exit(1)
  
      logging.info(
          "Namespace auto-detected to '%s' "
          "- you can override this with the --namespace option.", ns)
      return ns
docs: Try to automatically detect the URI namespace of the vocabulary.
  
      Return namespace as URIRef.