code: def test_grad_state(self):
      k = gpytorch.kernels.RBFKernel()
      X = torch.randn(2, 3)
      X.requires_grad = True
      lazy_tensor = k(X)
      self.assertTrue(lazy_tensor.to_dense().requires_grad)
      with torch.no_grad():
          lazy_tensor = k(X)
      self.assertFalse(lazy_tensor.to_dense().requires_grad)
  
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 12 for calling the TestLazyEvaluatedKernelTensorBatch obj's underlying member method code with example usage: obj.test_grad_state() without return types