code: def __len__(self) -> int:
      return len(self.data) - self.block_size
  
file_path: tnt/examples/mingpt/char_dataset.py
imports: from dataclasses import dataclass
  from typing import Dict, Tuple
  import fsspec
  import torch
  from torch.utils.data import Dataset
label_desc: Use image node_id 2 for calling the CharDataset obj's underlying member method code with example usage: obj.__len__() and returns: unknown