class_docstr: A dataset that provides helpers for batching.
class_docstr_tok: ["A","dataset","that","provides","helpers","for","batching","."]
code: def __len__(self):
      raise NotImplementedError
  
imports: import logging
  import numpy
  import torch.utils.data
  from fairseq.data import data_utils
label_desc: Use image node_id 2 for calling the FairseqDataset obj's underlying member method code with example usage: obj.__len__() without return types