code: def test_gradcheck(self, device):
      img = torch.rand(1, 2, 5, 4, device=device)
      guide = torch.rand(1, 2, 5, 4, device=device)
      img = tensor_to_gradcheck_var(img)  # to var
      guide = tensor_to_gradcheck_var(guide)
      self.gradcheck(joint_bilateral_blur, (img, guide, 3, 1, (1, 1)))
  
imports: import pytest
  import torch
  from kornia.filters import BilateralBlur, JointBilateralBlur, bilateral_blur, joint_bilateral_blur
  from kornia.testing import BaseTester, tensor_to_gradcheck_var
label_desc: Use image node_id 6 for calling the TestJointBilateralBlur obj's underlying member method code with example usage: obj.test_gradcheck(device) without return types