code: def testNaNGradFails(self):
      with ops.Graph().as_default() as g:
          with self.session(graph=g):
              x = array_ops.placeholder(dtypes.float32)
              with g.gradient_override_map({"Identity": "NaNGrad"}):
                  y = array_ops.identity(x)
                  error = gradient_checker.compute_gradient_error(
                      x, (), y, ()
                  )
                  # Typical test would assert error < max_err, so assert this test would
                  # raise AssertionError, since NaN is not < 1.0.
                  with self.assertRaisesRegex(
                      AssertionError, "False is not true"
                  ):
                      self.assertTrue(error < 1.0)
  
imports: import numpy
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gradient_checker
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import nn_ops
  import tensorflow.python.ops.nn_grad
  from tensorflow.python.platform import test
  from tensorflow.python.platform import tf_logging
label_desc: Use image node_id 10 for calling the GradientCheckerTest obj's underlying member method code with example usage: obj.testNaNGradFails() without return types