docs: private static ImmutableList<Range<Integer>> findAllOpenCloseParens(final String parse) {
      final ImmutableList.Builder<Range<Integer>> ret = ImmutableList.builder();
      final Stack<Integer> openPositions = new Stack<>();
      for (int pos = 0; pos < parse.length(); pos++) {
        // push
        if (parse.charAt(pos) == '(') {
          openPositions.push(pos);
        }
        // pop
        if (parse.charAt(pos) == ')') {
          Integer open = openPositions.pop();
          ret.add(Range.closed(open, pos));
        }
      }
  
      return ret.build();
    }