class_docstr: Abstract data generator.
class_docstr_tok: ["Abstract","data","generator","."]
docstr: Number of batches in the Sequence.
  
  Returns:
      The number of batches in the Sequence.
docstr_tok: ["Number","of","batches","in","the","Sequence",".","Returns",":","The","number","of","batches","in","the","Sequence","."]
code: def __len__(self) -> int:
      """Number of batches in the Sequence.
  
      Returns:
          The number of batches in the Sequence.
      """
      raise NotImplementedError
  
imports: import math
  from typing import List, Union, Text, Optional, Any, Tuple, Dict, cast
  import logging
  import scipy.sparse
  import numpy
  from tensorflow.keras.utils import Sequence
  from rasa.utils.tensorflow.constants import SEQUENCE, BALANCED
  from rasa.utils.tensorflow.model_data import RasaModelData, Data, FeatureArray
label_desc: Use image node_id 2 for calling the RasaDataGenerator obj's underlying member method code with example usage: obj.__len__() without return types