code: def _ema_replica_fn_graph(self):
      w = variables.Variable(
          [1.0],
          name="w",
          aggregation=variables.VariableAggregation.MEAN,
      )
      ema = moving_averages.ExponentialMovingAverage(0.8)
      w_apply = ema.apply([w])
      w_assign = w.assign_sub([0.5])
      return w_assign, w_apply, ema.average(w)
  
imports: from absl.testing import parameterized
  from tensorflow.python.distribute import combinations
  from tensorflow.python.distribute import strategy_combinations
  from tensorflow.python.distribute import strategy_test_lib
  from tensorflow.python.distribute import test_util
  from tensorflow.python.eager import def_function
  from tensorflow.python.eager import test
  from tensorflow.python.framework import constant_op
  from tensorflow.python.ops import variables
  from tensorflow.python.training import moving_averages
label_desc: Use image node_id 3 for calling the ExponentialMovingAverageTest obj's underlying member method code with example usage: obj._ema_replica_fn_graph() and returns: w_assign,  w_apply,  ema