code: def get_data_info(self, idx):
      return dict(
          width=self.shapes[idx][0],
          height=self.shapes[idx][1],
          flag=self.flag,
      )
  
imports: import bisect
  from unittest import TestCase
  from unittest.mock import patch
  import numpy
  from torch.utils.data import ConcatDataset, Dataset
  from mmdet.datasets.samplers import GroupMultiSourceSampler, MultiSourceSampler
label_desc: Use image node_id 4 for calling the DummyDataset obj's underlying member method code with example usage: obj.get_data_info(idx) and returns: dict