code: def _get_config_file_path(xdg_config_dir, xdg_config_file):
      
      for config_dir in BaseDirectory.load_config_paths(xdg_config_dir):
          path = join(config_dir, xdg_config_file)
          if isfile(path):
              return path
      raise ConfigFileError(
          'No configuration files could be located after searching for a file '
          'named "{0}" in the standard XDG configuration paths, such as '
          '"~/.config/{1}/".'.format(xdg_config_file, xdg_config_dir)
      )
docs: Search ``XDG_CONFIG_DIRS`` for a config file and return the first found.
  
      Search each of the standard XDG configuration directories for a
      configuration file. Return as soon as a configuration file is found. Beware
      that by the time client code attempts to open the file, it may be gone or
      otherwise inaccessible.
  
      :param xdg_config_dir: A string. The name of the directory that is suffixed
          to the end of each of the ``XDG_CONFIG_DIRS`` paths.
      :param xdg_config_file: A string. The name of the configuration file that
          is being searched for.
      :returns: A ``str`` path to a configuration file.
      :raises nailgun.config.ConfigFileError: When no configuration file can be
          found.