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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def run_mnist():
 """Run MNIST training and eval loop."""

  mnist_classifier = tf.estimator.Estimator(
      model_fn=model_fn,
      model_dir=FLAGS.model_dir)

  # Set up training and evaluation input functions.
  def train_input_fn():
    """Prepare data for training."""

    # When choosing shuffle buffer sizes, larger sizes result in better
    # randomness, while smaller sizes use less memory. MNIST is a small
    # enough dataset that we can easily shuffle the full epoch.
    ds = dataset.train(FLAGS.data_dir)
    ds_batched = ds.cache().shuffle(buffer_size=50000).batch(FLAGS.batch_size)

    # Iterate through the dataset a set number (`epochs_between_evals`) of times
    # during each training session.
    ds = ds_batched.repeat(FLAGS.epochs_between_evals)
    return ds

  def eval_input_fn():
    return dataset.test(FLAGS.data_dir).batch(
        FLAGS.batch_size).make_one_shot_iterator().get_next()

  # Train and evaluate model.
  for _ in range(FLAGS.train_epochs // FLAGS.epochs_between_evals):
    mnist_classifier.train(input_fn=train_input_fn, hooks=None)
    eval_results = mnist_classifier.evaluate(input_fn=eval_input_fn)
    print("\nEvaluation results:\n\t%s\n" % eval_results)