code: def test_wrap_optimizer(self):
      opt = gradient_descent_v1.GradientDescentOptimizer(1.0)
      opt = mixed_precision.enable_mixed_precision_graph_rewrite_v1(
          opt, 123.0
      )
      self.assertIsInstance(
          opt, loss_scale_optimizer_v1.MixedPrecisionLossScaleOptimizer
      )
      self.assertEqual(self.evaluate(opt._loss_scale()), 123.0)
  
imports: import os
  from absl.testing import parameterized
  from tensorflow.core.protobuf import config_pb2
  from tensorflow.python.client import session
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import config
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import test
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.training import gradient_descent
  from tensorflow.python.training.experimental import loss_scale_optimizer
  from tensorflow.python.training.experimental import mixed_precision
  from tensorflow.python.training.experimental import mixed_precision_global_state
label_desc: Use image node_id 3 for calling the MixedPrecisionTest obj's underlying member method code with example usage: obj.test_wrap_optimizer() without return types