code: def test_smoke(self, device, dtype):
      C, H, W = 3, 4, 5
      img = torch.rand(C, H, W, device=device, dtype=dtype)
      out = kornia.color.rgb_to_grayscale(img)
      assert out.device == img.device
      assert out.dtype == img.dtype
  
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 1 for calling the TestRgbToGrayscale obj's underlying member method code with example usage: obj.test_smoke(device, dtype) without return types