code: def is_valid_line(line):
      """
      Check if a line being read is a valid constituent
  
      The idea is that some "trees" are just a long list of words with
      no tree structure and need to be eliminated.
  
      :param line: constituent being read
      :return: True if it has open OR closing parenthesis.
      """
      if line.startswith("(") or line.endswith(")"):
          return True
  
      return False
  
file_path: stanza/stanza/utils/datasets/constituency/vtb_convert.py
imports: import argparse
  import os
  from collections import defaultdict
  from stanza.models.constituency.tree_reader import read_trees, MixedTreeError, UnlabeledTreeError
label_desc: Use image node_id 3 for calling a global function with example usage: is_valid_line(line) and returns: False, True