code: def create_linear_op(self):
      kern = gpytorch.kernels.AdditiveStructureKernel(
          gpytorch.kernels.RBFKernel(), num_dims=6
      )
      mat1 = torch.randn(5, 6)
      mat2 = mat1.detach().clone()
      return kern(mat1, mat2)
  
imports: import math
  import unittest
  from unittest.mock import MagicMock, patch
  import linear_operator
  import torch
  from linear_operator import to_dense
  from linear_operator.test.linear_operator_test_case import LinearOperatorTestCase
  import gpytorch
label_desc: Use image node_id 1 for calling the TestLazyEvaluatedKernelTensorAdditive obj's underlying member method code with example usage: obj.create_linear_op() and returns: kern