code: def test_gradcheck(self, device, dtype, kernel):
      sample = torch.ones(32, 32, device=device, dtype=dtype)
      sample = utils.tensor_to_gradcheck_var(sample)  # to var
      centers = torch.linspace(0, 255, 8, device=device, dtype=dtype)
      centers = utils.tensor_to_gradcheck_var(centers)
      assert gradcheck(
          TestImageHistogram2d.fcn,
          (sample, 0.0, 255.0, 256, None, centers, True, kernel),
          raise_exception=True,
          fast_mode=True,
      )
  
imports: import pytest
  import torch
  from packaging import version
  from torch.autograd import gradcheck
  import kornia
  import kornia.testing
  from kornia.testing import assert_close
label_desc: Use image node_id 4 for calling the TestImageHistogram2d obj's underlying member method code with example usage: obj.test_gradcheck(device, dtype, kernel) without return types