code: def __init__(self, length):
      self.length = length
      self.shapes = np.random.random((length, 2))
  
file_path: mmdetection/tests/test_datasets/test_samplers/test_batch_sampler.py
imports: from unittest import TestCase
  from unittest.mock import patch
  import numpy
  from mmengine.dataset import DefaultSampler
  from torch.utils.data import Dataset
  from mmdet.datasets.samplers import AspectRatioBatchSampler
label_desc: Use image node_id 1 to create a new DummyDataset object from inherited base classes: Dataset with example: obj = DummyDataset(length)