code: def test_coco_bbox_dataset(self):
      assert_is_bbox_dataset(
          self.dataset, len(coco_bbox_label_names), n_example=30
      )
  
      if self.return_area:
          for _ in range(10):
              i = np.random.randint(0, len(self.dataset))
              _, bbox, _, area = self.dataset[i][:4]
              self.assertIsInstance(area, np.ndarray)
              self.assertEqual(area.dtype, np.float32)
              self.assertEqual(area.shape, (bbox.shape[0],))
  
      if self.return_crowded:
          for _ in range(10):
              i = np.random.randint(0, len(self.dataset))
              example = self.dataset[i]
              crowded = example[-1]
              bbox = example[1]
              self.assertIsInstance(crowded, np.ndarray)
              self.assertEqual(crowded.dtype, np.bool)
              self.assertEqual(crowded.shape, (bbox.shape[0],))
  
              if not self.use_crowded:
                  np.testing.assert_equal(crowded, 0)
  
file_path: chainercv/tests/datasets_tests/coco_tests/test_coco_bbox_dataset.py
imports: import unittest
  import numpy
  from chainer import testing
  from chainer.testing import attr
  from chainercv.datasets import coco_bbox_label_names
  from chainercv.datasets import COCOBboxDataset
  from chainercv.utils import assert_is_bbox_dataset
label_desc: Use image node_id 2 for calling the TestCOCOBboxDataset obj's underlying member method code with example usage: obj.test_coco_bbox_dataset() without return types