code: def test_gradient(self):
      rng = np.random.default_rng(43)
      utt.verify_grad(
          self.op_class(),
          [rng.random((5, 4)), rng.random((5, 4))],
          n_tests=1,
          rng=TestProdOp.rng,
      )
  
imports: import unittest
  import pytensor
  from pytensor.graph.basic import Apply
  from pytensor.graph.op import Op
  from pytensor.tensor.type import TensorType
  from tests import unittest_tools
  from pytensor import tensor
  from pytensor.graph.basic import Apply
  from pytensor.tensor.type import dmatrix, matrix
  import numpy
  import pytensor
  from pytensor.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