code: def ordered_indices(self):
      return np.arange(self.num_items)
  
imports: import logging
  import numpy
  import torch
  from fairseq.data import Dictionary, FairseqDataset
  from fairseq.tasks import LegacyFairseqTask, register_task
label_desc: Use image node_id 8 for calling the DummyDataset obj's underlying member method code with example usage: obj.ordered_indices() and returns: np