code: def test_back_and_forth(self, device, dtype):
      data_bgr = torch.rand(1, 3, 3, 2, device=device, dtype=dtype)
      data_rgb = kornia.color.bgr_to_rgb(data_bgr)
      data_bgr_new = kornia.color.rgb_to_bgr(data_rgb)
      self.assert_close(data_bgr, data_bgr_new)
  
imports: import pytest
  import torch
  from torch.autograd import gradcheck
  import kornia
  from kornia.testing import BaseTester
label_desc: Use image node_id 4 for calling the TestRgbToBgr obj's underlying member method code with example usage: obj.test_back_and_forth(device, dtype) without return types