class_docstr: Abstract data generator.
class_docstr_tok: ["Abstract","data","generator","."]
docstr: Update the data after every epoch.
docstr_tok: ["Update","the","data","after","every","epoch","."]
code: def on_epoch_end(self) -> None:
      """Update the data after every epoch."""
      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 4 for calling the RasaDataGenerator obj's underlying member method code with example usage: obj.on_epoch_end() without return types