code: def tokenize(self, tokenizer):
      all_tokenized_tokens = []
      labels = []
      label_mask = []
      for token, pos in zip_equal(self.tokens, self.pos_list):
          # Tokenize each "token" separately, assign label only to first token
          tokenized = tokenizer.tokenize(token)
          # If the token can't be tokenized, or is too long, replace with a single <unk>
          if (
              len(tokenized) == 0
              or len(tokenized) > ARBITRARY_OVERLY_LONG_WORD_CONSTRAINT
          ):
              tokenized = [tokenizer.unk_token]
          all_tokenized_tokens += tokenized
          padding_length = len(tokenized) - 1
          labels += [UdposTask.LABEL_TO_ID.get(pos, None)] + [
              None
          ] * padding_length
          label_mask += [1] + [0] * padding_length
  
      return TokenizedExample(
          guid=self.guid,
          tokens=all_tokenized_tokens,
          labels=labels,
          label_mask=label_mask,
      )
  
imports: import numpy
  import torch
  from dataclasses import dataclass
  from typing import List, Union
  from jiant.tasks.core import BaseExample, BaseTokenizedExample, BaseDataRow, BatchMixin, Task, TaskTypes
  from jiant.tasks.lib.templates.shared import labels_to_bimap, create_input_set_from_tokens_and_segments, construct_single_input_tokens_and_segment_ids, pad_single_with_feat_spec
  from jiant.utils.python.datastructures import zip_equal
  from jiant.utils.python.io import read_file_lines
label_desc: Use image node_id 1 for calling the Example obj's underlying member method code with example usage: obj.tokenize(tokenizer) and returns: TokenizedExample