import tensorflow as tf

      self.saver_train = tf.train.Saver(self.vars)

  def __build_eval(self):
    """Build the evaluation graph."""

    with tf.Graph().as_default():
      # create a TF session for the current graph
      config = tf.ConfigProto()
      if FLAGS.enbl_multi_gpu:
        config.gpu_options.visible_device_list = str(mgw.local_rank())  # pylint: disable=no-member
      else:
        config.gpu_options.visible_device_list = '0'  # pylint: disable=no-member
      self.sess_eval = tf.Session(config=config)

