code: def _GetConfigValue(self, config_parser, section_name, value_name):
      
      try:
        return config_parser.get(section_name, value_name)
      except configparser.NoOptionError:
        return None
docs: Retrieves a value from the config parser.
  
      Args:
        config_parser (ConfigParser): configuration parser.
        section_name (str): name of the section that contains the value.
        value_name (str): name of the value.
  
      Returns:
        object: configuration value or None if the value does not exists.