code: def __len__(self):
      return len(self.files)
  
file_path: calamari/calamari_ocr/ocr/dataset/datareader/extended_prediction.py
imports: import codecs
  import zlib
  from dataclasses import dataclass, field
  from typing import List, Type
  from paiargparse import pai_dataclass
  from calamari_ocr.ocr.dataset.datareader.base import CalamariDataGenerator, CalamariDataGeneratorParams
  from calamari_ocr.ocr.predict.params import Predictions
  from calamari_ocr.utils import split_all_ext, glob_all
label_desc: Use image node_id 1 for calling the ExtendedPredictionDataParams obj's underlying member method code with example usage: obj.__len__() and returns: len