class_docstr: Open Retrieval Question Answering evaluation using Google NQ dataset.
class_docstr_tok: ["Open","Retrieval","Question","Answering","evaluation","using","Google","NQ","dataset","."]
code: def __len__(self):
      return len(self.samples)
  
imports: from abc import ABC
  import csv
  from collections import OrderedDict
  import numpy
  import torch
  from torch.utils.data import DataLoader
  from torch.utils.data import Dataset, BatchSampler
  from megatron import print_rank_0, get_args, get_tokenizer
  from megatron.data.biencoder_dataset_utils import make_attention_mask
label_desc: Use image node_id 2 for calling the NQDataset obj's underlying member method code with example usage: obj.__len__() and returns: len