code: def __len__(self):
      return len(self.source_text)
  
file_path: TextBox/textbox/data/abstract_dataset.py
imports: import os
  import torch, warnings
  import math
  from torch.utils.data import DataLoader, Dataset
  from textbox import CLM_MODELS
  from typing import List
  from torch.nn.utils.rnn import pad_sequence
  from textbox.data.misc import load_data, _pad_sequence
label_desc: Use image node_id 2 for calling the AbstractDataset obj's underlying member method code with example usage: obj.__len__() and returns: len