code: def file_config(filename=None):
      
      logger.debug('On entry into file_config(), filename = {}'.format(filename))
  
      if filename is None:
          filename = CONFIG_DEFAULT_PATH
  
      logger.debug('file_config() will try to open `{}`'.format(filename))
      with open(filename) as f:
          try:
              config = json.load(f)
          except ValueError as err:
              raise exceptions.ConfigurationError(
                  'Failed to parse the JSON configuration from `{}`, {}'.format(filename, err)
              )
  
          logger.info('Configuration loaded from `{}`'.format(filename))
  
      return config
docs: Returns the config values found in a configuration file.
  
      Args:
          filename (str): the JSON file with the configuration values.
              If ``None``, CONFIG_DEFAULT_PATH will be used.
  
      Returns:
          dict: The config values in the specified config file (or the
                file at CONFIG_DEFAULT_PATH, if filename == None)