input: Write a python function to reshape and normalize the MNIST dataset.
  assert np.array_equal(normalize_mnist(x_train)[0], x_train.reshape((x_train.shape[0], 28, 28, 1)) / 255.0)
  assert np.array_equal(normalize_mnist(x_test)[0], x_test.reshape((x_test.shape[0], 28, 28, 1)) / 255.0)
output: def normalize_mnist(data):
      reshaped_data = data.reshape((data.shape[0], 28, 28, 1))
      normalized_data = reshaped_data / 255.0
      return normalized_data