def METHOD_NAME(config):
  """Implements the --fix option: overwrites missing or out-of-date files.
  Args:
    config: the Config object for this test.
  """
  file_pairs = _GetFilePairs(config)
  missing_files, stale_files = _GetMissingAndStaleFiles(file_pairs)
  _CopyFiles(stale_files + missing_files)