code: def testBasicFunctionalPositionalArg(self):
      def forward(a, b):
          mm = math_ops.matmul(a, b)
          return math_ops.reduce_sum(mm)
  
      aa = constant_op.constant([[1.0, 0.0], [0.0, 1.0]])
      bb = constant_op.constant([[1.0, 2.0], [3.0, 4.0]])
      (da,) = backprop.gradients_function(forward, [0])(aa, bb)
      self.assertAllEqual(
          da,
          math_ops.matmul(
              array_ops.ones_like(aa), array_ops.transpose(bb)
          ).numpy(),
      )
  
imports: from tensorflow.python.eager import backprop
  from tensorflow.python.eager import context
  from tensorflow.python.eager import record
  from tensorflow.python.eager import test
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import custom_gradient
  from tensorflow.python.ops import gradients_impl
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import nn_grad
  from tensorflow.python.ops import nn_ops
  from tensorflow.python.ops import variables
label_desc: Use image node_id 3 for calling the TapeTest obj's underlying member method code with example usage: obj.testBasicFunctionalPositionalArg() and returns: math_ops