code: def test_gradcheck(self, batch_size, device, dtype):
      trans_01 = identity_matrix(batch_size, device=device, dtype=dtype)
      trans_02 = identity_matrix(batch_size, device=device, dtype=dtype)
  
      trans_01 = utils.tensor_to_gradcheck_var(trans_01)  # to var
      trans_02 = utils.tensor_to_gradcheck_var(trans_02)  # to var
      assert gradcheck(
          kgl.relative_transformation,
          (trans_01, trans_02),
          raise_exception=True,
          fast_mode=True,
      )
  
imports: import pytest
  import torch
  from torch.autograd import gradcheck
  import kornia
  import kornia.geometry.linalg
  import kornia.testing
  from kornia.testing import BaseTester, assert_close
label_desc: Use image node_id 5 for calling the TestRelativeTransformation obj's underlying member method code with example usage: obj.test_gradcheck(batch_size, device, dtype) without return types