code: def test_defaultbox_generator(self):
      images = torch.zeros(2, 3, 15, 15)
      features = [torch.zeros(2, 8, 1, 1)]
      image_shapes = [i.shape[-2:] for i in images]
      images = ImageList(images, image_shapes)
  
      model = self._init_test_defaultbox_generator()
      model.eval()
      dboxes = model(images, features)
  
      dboxes_output = torch.tensor(
          [
              [6.3750, 6.3750, 8.6250, 8.6250],
              [4.7443, 4.7443, 10.2557, 10.2557],
              [5.9090, 6.7045, 9.0910, 8.2955],
              [6.7045, 5.9090, 8.2955, 9.0910],
          ]
      )
  
      assert len(dboxes) == 2
      assert tuple(dboxes[0].shape) == (4, 4)
      assert tuple(dboxes[1].shape) == (4, 4)
      torch.testing.assert_close(
          dboxes[0], dboxes_output, rtol=1e-5, atol=1e-8
      )
      torch.testing.assert_close(
          dboxes[1], dboxes_output, rtol=1e-5, atol=1e-8
      )
  
file_path: vision/test/test_models_detection_anchor_utils.py
imports: import pytest
  import torch
  from common_utils import assert_equal
  from torchvision.models.detection.anchor_utils import AnchorGenerator, DefaultBoxGenerator
  from torchvision.models.detection.image_list import ImageList
label_desc: Use image node_id 6 for calling the Tester obj's underlying member method code with example usage: obj.test_defaultbox_generator() without return types