import tensorflow as tf

          all_top_5_ops.append(results[2])

        if self.variable_mgr.retain_tower_updates(device_num):
          # Retain the Batch Normalization updates operations only from the
          # first tower. Ideally, we should grab the updates from all towers but
          # these stats accumulate extremely fast so we can ignore the other
          # stats from the other towers without significant detriment.
          update_ops = tf.get_collection(tf.GraphKeys.UPDATE_OPS, name_scope)
          staging_delta_ops = list(self.variable_mgr.staging_delta_ops)

    if not update_ops:
      update_ops = tf.get_collection(tf.GraphKeys.UPDATE_OPS, name_scope)
    enqueue_ops.append(tf.group(*gpu_copy_stage_ops))
    if self.variable_mgr.supports_staged_vars():
