code: def test_gradcheck(self, device):
      vec = torch.ones(
          2, 3, device=device, requires_grad=True, dtype=torch.float64
      )
      assert gradcheck(
          epi.cross_product_matrix,
          (vec,),
          raise_exception=True,
          fast_mode=True,
      )
  
file_path: kornia/test/geometry/epipolar/test_numeric.py
imports: import pytest
  import torch
  from torch.autograd import gradcheck
  import kornia
  import kornia.geometry.epipolar
  from kornia.testing import assert_close
label_desc: Use image node_id 6 for calling the TestSkewSymmetric obj's underlying member method code with example usage: obj.test_gradcheck(device) without return types