class_docstr: Pytorch class for ART speech recognizers. This class is used to define common methods for using inside pytorch
  imperceptible asr attack.
docstr: Put the estimator in the training mode.
code: def to_training_mode(self) -> None:
      """
      Put the estimator in the training mode.
      """
      raise NotImplementedError
  
file_path: adversarial-robustness-toolbox/art/estimators/speech_recognition/speech_recognizer.py
imports: from abc import ABC, abstractmethod
  from typing import Tuple, TYPE_CHECKING
  import numpy
label_desc: Use image node_id 2 for calling the PytorchSpeechRecognizerMixin obj's underlying member method code with example usage: obj.to_training_mode() without return types