docs: def main():
      """Main function"""
      parser = OptionParser()
      parser.add_option(
          '-c', '--config',
          help='configuration file',
          dest='filename',
          type='str',
          default='/etc/sachannelupdate/sachannelupdate.ini')
      parser.add_option(
          '-d', '--delete',
          help='Deletes existing rules',
          dest='cleanup',
          action="store_true",
          default=False,)
      options, _ = parser.parse_args()
      if not os.path.isfile(options.filename):
          raise SaChannelUpdateConfigError(
              "The configuration file: %s does not exist" % options.filename)
  
      config = ConfigParser()
      config.read(options.filename)
      try:
          # pylint: disable=protected-access
          entry(config._sections['settings'], options.cleanup)
      except BaseException as msg:
          error(msg)