code: def test_unkify(self):
      map_token_unkified = {"": "<unk>", "72": "<unk>-NUM"}
  
      for token, expected_unkified in map_token_unkified.items():
          self.assertEqual(unkify(token), expected_unkified)
  
imports: import json
  import os
  import random
  import shutil
  import tempfile
  import unittest
  import numpy
  import torch
  from pytext.utils import recursive_map, round_seq, set_random_seeds
  from pytext.utils.data import align_slot_labels, merge_token_labels_to_slot, strip_bio_prefix, unkify
  from pytext.utils.distributed import get_shard_range
  from pytext.utils.file_io import chunk_file, PathManager
  from pytext.utils.meter import TimeMeter
  from pytext.utils.test import import_tests_module
label_desc: Use image node_id 4 for calling the UtilTest obj's underlying member method code with example usage: obj.test_unkify() without return types