class_docstr: Implements conditional random fields (CRF) to do named entity recognition.
class_docstr_tok: ["Implements","conditional","random","fields","(","CRF",")","to","do","named","entity","recognition","."]
docstr: Persist this model into the passed directory.
docstr_tok: ["Persist","this","model","into","the","passed","directory","."]
code: def persist(self) -> None:
      """Persist this model into the passed directory."""
      import joblib
  
      with self._model_storage.write_to(self._resource) as model_dir:
          if self.entity_taggers:
              for idx, (name, entity_tagger) in enumerate(
                  self.entity_taggers.items()
              ):
                  model_file_name = model_dir / f"{idx}{name}.pkl"
                  joblib.dump(entity_tagger, model_file_name)
  
imports: from __future__ import annotations
  from collections import OrderedDict
  from enum import Enum
  import logging
  import typing
  import numpy
  from typing import Any, Dict, List, Optional, Text, Tuple, Callable, Type
  import rasa.nlu.utils.bilou_utils
  import rasa.shared.utils.io
  import rasa.utils.train_utils
  from rasa.engine.graph import GraphComponent, ExecutionContext
  from rasa.engine.recipes.default_recipe import DefaultV1Recipe
  from rasa.engine.storage.resource import Resource
  from rasa.engine.storage.storage import ModelStorage
  from rasa.nlu.test import determine_token_labels
  from rasa.nlu.tokenizers.spacy_tokenizer import POS_TAG_KEY
  from rasa.nlu.extractors.extractor import EntityExtractorMixin
  from rasa.nlu.tokenizers.tokenizer import Token, Tokenizer
  from rasa.shared.nlu.training_data.training_data import TrainingData
  from rasa.shared.nlu.training_data.message import Message
  from rasa.nlu.constants import TOKENS_NAMES
  from rasa.shared.nlu.constants import TEXT, ENTITIES, ENTITY_ATTRIBUTE_TYPE, ENTITY_ATTRIBUTE_GROUP, ENTITY_ATTRIBUTE_ROLE, NO_ENTITY_TAG, SPLIT_ENTITIES_BY_COMMA, SPLIT_ENTITIES_BY_COMMA_DEFAULT_VALUE
  from rasa.shared.constants import DOCS_URL_COMPONENTS
  from rasa.utils.tensorflow.constants import BILOU_FLAG, FEATURIZERS
label_desc: Use image node_id 15 for calling the CRFEntityExtractor obj's underlying member method code with example usage: obj.persist() without return types