docs: public static ImmutableList<File> loadFileList(final CharSource source) throws IOException {
      final ImmutableList.Builder<File> ret = ImmutableList.builder();
  
      for (final String filename : source.readLines()) {
        if (!filename.isEmpty() && !isCommentLine(filename)) {
          ret.add(new File(filename.trim()));
        }
      }
  
      return ret.build();
    }