class_docstr: Open Retrieval base dataset class.
class_docstr_tok: ["Open","Retrieval","base","dataset","class","."]
code: def __len__(self):
      return len(self.samples)
  
imports: import json
  import random
  from abc import ABC
  from abc import abstractmethod
  import numpy
  from torch.utils.data import Dataset
  from megatron import print_rank_0, get_args
  from megatron.data.biencoder_dataset_utils import make_attention_mask
label_desc: Use image node_id 2 for calling the OpenRetrievalAbstractDataset obj's underlying member method code with example usage: obj.__len__() and returns: len