docs: def get_option(option_name, section_name="main", default=_sentinel, cfg_file=cfg_file):
      """ Returns a specific option specific in a config file
  
      Arguments:
          option_name  -- Name of the option (example host_name)
          section_name -- Which section of the config (default: name)
  
      examples:
      >>> get_option("some option", default="default result")
      'default result'
      """
      defaults = get_defaults()
  
      # As a quality issue, we strictly disallow looking up an option that does not have a default
      # value specified in the code
      #if option_name not in defaults.get(section_name, {}) and default == _sentinel:
      #    raise ValueError("There is no default value for Option %s in section %s" % (option_name, section_name))
  
      # If default argument was provided, we set variable my_defaults to that
      # otherwise use the global nago defaults
      if default != _sentinel:
          my_defaults = {option_name: default}
      else:
          my_defaults = defaults.get('section_name', {})
  
      # Lets parse our configuration file and see what we get
      parser = get_parser(cfg_file)
      return parser.get(section_name, option_name, vars=my_defaults)