code: def check_well_form(tree_str):
      return find_bracket_num(tree_str) == 0
  
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 4 for calling a global function with example usage: check_well_form(tree_str) and returns: unknown