code: def _add_instance_ids(self, key="instance_id"):
      for idx, ann in enumerate(self.annotation):
          ann[key] = str(idx)
  
file_path: lavis/lavis/datasets/datasets/base_dataset.py
imports: import json
  from typing import Iterable
  import pandas
  import torch
  from torch.utils.data import Dataset, ConcatDataset
  from torch.utils.data.dataloader import default_collate
label_desc: Use image node_id 5 for calling the BaseDataset obj's underlying member method code with example usage: obj._add_instance_ids(key) without return types