code: def add_bracket(tree_str):
      """add right bracket to fix ill-formed expression"""
      tree_str_list = tree_str.split()
      bracket_num = find_bracket_num(tree_str_list)
      tree_str_list += [right_bracket] * bracket_num
      return " ".join(tree_str_list)
  
imports: from collections import Counter
  import logging
  from nltk.tree import ParentedTree
  import re
  from typing import Tuple, List, Dict
  from ...extraction.constants import null_span, type_start, type_end, span_start
  from ...extraction.predict_parser.predict_parser import PredictParser
  from ...extraction.predict_parser.utils import fix_unk_from_text
label_desc: Use image node_id 7 for calling a global function with example usage: add_bracket(tree_str) and returns: str