code: public static ImmutableListMultimap<String, File> loadStringToFileListMultimap(
        final CharSource source) throws IOException {
      return loadMultimap(source, Functions.<String>identity(), FileFunction.INSTANCE,
          IsCommentLine.INSTANCE);
    }
docs: Reads an {@link ImmutableListMultimap} from a {@link CharSource}, where each line is a
  key, a tab character ("\t"), and a value. Blank lines and lines beginning with "#" are ignored.