def _FindBestFileForSource(self, source, min_file_size=None, max_mtime_age_days=None):
    """Find the best file (newest over X size) to use for a given source type.

    Args:
      source: source type
      min_file_size: What the minimum allowable file size is for this source (int)
      max_mtime_age_days: Maximum days old the file can be for this source (int)

    Returns:
      A file path.
    """
    found = []
    for path in self._GetSourceSearchPaths(source):
      if not os.path.isabs(path):
        path = util.FindDataFile(path)

      for filename in glob.glob(path):
        if min_file_size and os.path.getsize(filename) < min_file_size:
          self.msg((filename, os.path.getsize(filename)) % 'Skipping %s (only %sb)')
        else:
          try:
            fp = open(filename, 'rb')
            fp.close()
            found.append(filename)
          except IOError:
            self.msg('Skipping %s (could not open)' % filename)

    if found:
      newest = sorted(found, key=os.path.getmtime)[-1]
      age_days = (time.time() - os.path.getmtime(newest)) / 86400
      if max_mtime_age_days and age_days > max_mtime_age_days:
        pass
#        self.msg('Skipping %s (%2.0fd old)' % (newest, age_days))
      else:
        return newest
    else:
      return None
dataset/ETHPy150Open catap/namebench/libnamebench/data_sources.py/DataSources._FindBestFileForSource/swapped operands of `%`