class_docstr: Exception that can be raised if story cannot be featurized.
class_docstr_tok: ["Exception","that","can","be","raised","if","story","can","not","be","featurized","."]
code: def __str__(self) -> Text:
      return self.message
  
imports: from __future__ import annotations
  from pathlib import Path
  from collections import defaultdict
  from abc import abstractmethod
  import jsonpickle
  import logging
  from tqdm import tqdm
  from typing import Tuple, List, Optional, Dict, Text, Union, Any, Iterator, Set, DefaultDict, cast
  import numpy
  from rasa.core.featurizers.single_state_featurizer import SingleStateFeaturizer
  from rasa.core.featurizers.precomputation import MessageContainerForCoreFeaturization
  from rasa.core.exceptions import InvalidTrackerFeaturizerUsageError
  import rasa.shared.core.trackers
  import rasa.shared.utils.io
  from rasa.shared.nlu.constants import TEXT, INTENT, ENTITIES, ACTION_NAME
  from rasa.shared.nlu.training_data.features import Features
  from rasa.shared.core.trackers import DialogueStateTracker
  from rasa.shared.core.domain import State, Domain
  from rasa.shared.core.events import Event, ActionExecuted, UserUttered
  from rasa.shared.core.constants import USER, ACTION_UNLIKELY_INTENT_NAME, PREVIOUS_ACTION
  from rasa.shared.exceptions import RasaException
  from rasa.utils.tensorflow.constants import LABEL_PAD_ID
  from rasa.utils.tensorflow.model_data import ragged_array_to_ndarray
label_desc: Use image node_id 2 for calling the InvalidStory obj's underlying member method code with example usage: obj.__str__() and returns: self