code: def __len__(self):
      return len(self.data_lines)
  
file_path: PaddleOCR/ppocr/data/pubtab_dataset.py
imports: import numpy
  import os
  import random
  from paddle.io import Dataset
  import json
  from copy import deepcopy
  from .imaug import transform, create_operators
label_desc: Use image node_id 6 for calling the PubTabDataSet obj's underlying member method code with example usage: obj.__len__() and returns: len