code: def featurize(self, tokenizer, feat_spec: FeaturizationSpec):
      raise NotImplementedError
  
imports: import numpy
  from typing import NamedTuple, Mapping, Dict
  from enum import Enum
  from dataclasses import dataclass
  import torch
  import torch.utils.data.dataloader
  from jiant.utils.python.datastructures import ExtendedDataClassMixin, combine_dicts
label_desc: Use image node_id 1 for calling the BaseTokenizedExample obj's underlying member method code with example usage: obj.featurize(tokenizer, feat_spec) without return types