title: AttributeError: 'collections.OrderedDict' object has no attribute 'train'
body: <pre><code>with summary_writer.as_default():
    for round_num in range(1, NUM_ROUNDS):
      state, metrics = iterative_process.next(state, federated_train_data)
      # for name, value in metrics.train._asdict().items():
      tf.summary.scalar('metrics', metrics.train._asdict().itrems(), step=round_num)
  </code></pre>
  <p>I am just stuck here. I am getting error messages as:
  <em>AttributeError: 'collections.OrderedDict' object has no attribute 'train'</em>
  Metrics looks like this:</p>
  <pre><code>metrics=OrderedDict([('broadcast', ()), ('aggregation', ()), ('train', OrderedDict([('sparse_categorical_accuracy', 0.12695473), ('loss', 3.0522373)]))])
  </code></pre>
  <p>Any help will be highly appreciated.</p>