code: def setUp(self):
      np.random.seed(42)
      self.dataset_overfit = MockDataset(1)
  
imports: import unittest
  from collections import defaultdict
  from dataclasses import dataclass
  from itertools import product
  import numpy
  import torch
  from pytorch3d.implicitron.dataset.data_loader_map_provider import DoublePoolBatchSampler
  from pytorch3d.implicitron.dataset.dataset_base import DatasetBase
  from pytorch3d.implicitron.dataset.frame_data import FrameData
  from pytorch3d.implicitron.dataset.scene_batch_sampler import SceneBatchSampler
label_desc: Use image node_id 1 for calling the TestSceneBatchSampler obj's underlying member method code with example usage: obj.setUp() without return types