code: def _grad(self, test_func, argnums=0):
      def _f(*params):
          with backprop.GradientTape() as tape:
              tape.watch(params)
              output = test_func(*params)
          return tape.gradient(output, params[argnums])
  
      return _f
  
imports: import functools
  from absl.testing import parameterized
  from xla.service import hlo_pb2
  from tensorflow.python.distribute.cluster_resolver import tpu_cluster_resolver
  from tensorflow.python.eager import backprop
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import config
  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 custom_gradient
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import googletest
  from tensorflow.python.platform import test
label_desc: Use image node_id 2 for calling the RecomputeGradMemoryTest obj's underlying member method code with example usage: obj._grad(test_func, argnums) and returns: _f, tape