code: def test_update_mirrored_variable(self, strategy):
      # It's very rare to update aggregation=ON_WRITE variables in the forward
      # path, and this test case is mainly for completeness.
  
      class Model(tf.Module):
          def __init__(self):
              self.v = tf.Variable(
                  0.0,
                  synchronization=tf.VariableSynchronization.ON_WRITE,
                  aggregation=tf.VariableAggregation.MEAN,
              )
  
          @tf.function(input_signature=[])
          def update(self):
              self.v.assign_add(1.0)
  
      export_dir = self.get_temp_dir()
      with strategy.scope():
          m = Model()
          tf.saved_model.save(m, export_dir)
  
      loaded = tf.saved_model.load(export_dir)
      self.assertEqual(self.evaluate(loaded.v), 0.0)
      loaded.update()
      self.assertEqual(self.evaluate(loaded.v), 1.0)
  
imports: import os
  from absl.testing import parameterized
  import tensorflow
  import tensorflow.compat.v1
  from tensorflow.python.distribute import combinations
  from tensorflow.python.distribute import multi_worker_test_base
  from tensorflow.python.distribute import parameter_server_strategy_v2
  from tensorflow.python.distribute import sharded_variable
  from tensorflow.python.distribute import strategy_combinations
  from tensorflow.python.distribute import test_util
  from tensorflow.python.distribute import values
  from tensorflow.python.eager import context
  from tensorflow.python.eager import test
  from tensorflow.python.ops import lookup_ops
label_desc: Use image node_id 4 for calling the SaveAndLoadForServingTest obj's underlying member method code with example usage: obj.test_update_mirrored_variable(strategy) without return types