code: def test_gradient(self):
      utt.verify_grad(
          self.op_class(),
          [np.random.rand(5, 4), np.random.rand(5, 4)],
          n_tests=1,
          rng=TestProdOp.rng,
      )
  
imports: from __future__ import absolute_import, print_function, division
  import unittest
  import theano
  import numpy
  from theano.gof import Op, Apply
  from theano import tensor, function, printing
  from theano.tests import unittest_tools
  import theano
  import numpy
  from theano.compile.ops import as_op
label_desc: Use image node_id 3 for calling the TestProdOp obj's underlying member method code with example usage: obj.test_gradient() without return types