code: def test_opencv(self, device, dtype):
      data = torch.tensor(
          [
              [
                  [
                      0.3944633,
                      0.8597369,
                      0.1670904,
                      0.2825457,
                      0.0953912,
                  ],
                  [
                      0.1251704,
                      0.8020709,
                      0.8933256,
                      0.9170977,
                      0.1497008,
                  ],
                  [
                      0.2711633,
                      0.1111478,
                      0.0783281,
                      0.2771807,
                      0.5487481,
                  ],
                  [
                      0.0086008,
                      0.8288748,
                      0.9647092,
                      0.8922020,
                      0.7614344,
                  ],
                  [
                      0.2898048,
                      0.1282895,
                      0.7621747,
                      0.5657831,
                      0.9918593,
                  ],
              ],
              [
                  [
                      0.5414237,
                      0.9962701,
                      0.8947155,
                      0.5900949,
                      0.9483274,
                  ],
                  [
                      0.0468036,
                      0.3933847,
                      0.8046577,
                      0.3640994,
                      0.0632100,
                  ],
                  [
                      0.6171775,
                      0.8624780,
                      0.4126036,
                      0.7600935,
                      0.7279997,
                  ],
                  [
                      0.4237089,
                      0.5365476,
                      0.5591233,
                      0.1523191,
                      0.1382165,
                  ],
                  [
                      0.8932794,
                      0.8517839,
                      0.7152701,
                      0.8983801,
                      0.5905426,
                  ],
              ],
              [
                  [
                      0.2869580,
                      0.4700376,
                      0.2743714,
                      0.8135023,
                      0.2229074,
                  ],
                  [
                      0.9306560,
                      0.3734594,
                      0.4566821,
                      0.7599275,
                      0.7557513,
                  ],
                  [
                      0.7415742,
                      0.6115875,
                      0.3317572,
                      0.0379378,
                      0.1315770,
                  ],
                  [
                      0.8692724,
                      0.0809556,
                      0.7767404,
                      0.8742208,
                      0.1522012,
                  ],
                  [
                      0.7708948,
                      0.4509611,
                      0.0481175,
                      0.2358997,
                      0.6900532,
                  ],
              ],
          ],
          device=device,
          dtype=dtype,
      )
  
      # Output data generated with OpenCV 4.1.1: cv2.cvtColor(img_np, cv2.COLOR_BGR2GRAY)
      expected = torch.tensor(
          [
              [
                  [
                      0.4485849,
                      0.8233618,
                      0.6262833,
                      0.6218331,
                      0.6341921,
                  ],
                  [
                      0.3200093,
                      0.4340172,
                      0.7107211,
                      0.5454938,
                      0.2801398,
                  ],
                  [
                      0.6149265,
                      0.7018101,
                      0.3503231,
                      0.4891168,
                      0.5292346,
                  ],
                  [
                      0.5096100,
                      0.4336508,
                      0.6704276,
                      0.4525143,
                      0.2134447,
                  ],
                  [
                      0.7878902,
                      0.6494595,
                      0.5211386,
                      0.6623823,
                      0.6660464,
                  ],
              ]
          ],
          device=device,
          dtype=dtype,
      )
  
      img_gray = kornia.color.bgr_to_grayscale(data)
      assert_close(img_gray, expected)
  
imports: import pytest
  import torch
  from torch.autograd import gradcheck
  import kornia
  from kornia.testing import BaseTester, assert_close
  from kornia.utils._compat import torch_version
label_desc: Use image node_id 4 for calling the TestBgrToGrayscale obj's underlying member method code with example usage: obj.test_opencv(device, dtype) without return types