code: def test_gradcheck(self, device):
      points = torch.rand(
          1,
          8,
          2,
          device=device,
          dtype=torch.float64,
          requires_grad=True,
      )
      K = torch.rand(1, 3, 3, device=device, dtype=torch.float64)
      new_K = torch.rand(1, 3, 3, device=device, dtype=torch.float64)
      distCoeff = torch.rand(1, 4, device=device, dtype=torch.float64)
  
      gradcheck(undistort_points, (points, K, distCoeff, new_K))
  
imports: import pytest
  import torch
  from kornia.geometry.calibration.undistort import undistort_image, undistort_points
  from kornia.testing import assert_close, gradcheck
label_desc: Use image node_id 7 for calling the TestUndistortPoints obj's underlying member method code with example usage: obj.test_gradcheck(device) without return types