code: def testFetchVariableList(self):
      opt = training.SyncReplicasOptimizer(
          opt=adam.AdamOptimizer(0.01),
          replicas_to_aggregate=1,
          total_num_replicas=1,
      )
      v = variable_v1.VariableV1([0.0], name="fetch_variable_test")
      global_step = variable_v1.VariableV1(
          0, name="global_step", trainable=False
      )
      opt.minimize(v, global_step=global_step)
      opt_variables = opt.variables()
      beta1_power, beta2_power = opt._opt._get_beta_accumulators()
      self.assertIn(beta1_power, opt_variables)
      self.assertIn(beta2_power, opt_variables)
  
imports: import time
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import indexed_slices
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.framework.test_util import create_local_cluster
  from tensorflow.python.ops import variable_v1
  from tensorflow.python.platform import test
  from tensorflow.python.training import adam
  from tensorflow.python.training import gradient_descent
  from tensorflow.python.training import training
label_desc: Use image node_id 3 for calling the SyncReplicasOptimizerHookTest obj's underlying member method code with example usage: obj.testFetchVariableList() without return types