code: def test_non_stationary_base(self):
      base_kernel = LinearKernel()
      with self.assertRaisesRegex(
          RuntimeError,
          "The base_kernel for GridKernel must be stationary.",
      ):
          GridKernel(base_kernel, grid)
  
file_path: gpytorch/test/kernels/test_grid_kernel.py
imports: import unittest
  import torch
  from linear_operator.operators import KroneckerProductLinearOperator
  import gpytorch
  from gpytorch.kernels import GridKernel, LinearKernel, RBFKernel
  from gpytorch.utils.grid import create_data_from_grid
label_desc: Use image node_id 7 for calling the TestGridKernel obj's underlying member method code with example usage: obj.test_non_stationary_base() without return types