docs: def _download_ontology(url, local_file):
      """Download the ontology and stores it in CLASSIFIER_WORKDIR."""
      current_app.logger.debug(
          "Copying remote ontology '%s' to file '%s'." % (url, local_file)
      )
      try:
          request = requests.get(url, stream=True)
          if request.status_code == 200:
              with open(local_file, 'wb') as f:
                  for chunk in request.iter_content(chunk_size):
                      f.write(chunk)
      except IOError as e:
          current_app.logger.exception(e)
          return False
      else:
          current_app.logger.debug("Done copying.")
          return True