code: def check_gcdt_update():
      
      try:
          inst_version, latest_version = get_package_versions('gcdt')
          if inst_version < latest_version:
              log.warn('Please consider an update to gcdt version: %s' %
                                   latest_version)
      except GracefulExit:
          raise
      except Exception:
          log.warn('PyPi appears to be down - we currently can\'t check for newer gcdt versions')
docs: Check whether a newer gcdt is available and output a warning.