Generate MNIST examples as dicts.

    Args:
      num_examples (int): The number of example.
      data_path (str): Path to the data files
      label_path (str): Path to the labels

    Yields:
      Generator yielding the next examples

def _generate_examples(self, num_examples, data_path, label_path):
    """Generate MNIST examples as dicts.

    Args:
      num_examples (int): The number of example.
      data_path (str): Path to the data files
      label_path (str): Path to the labels

    Yields:
      Generator yielding the next examples
    """
    images = _extract_mnist_images(data_path, num_examples)
    labels = _extract_mnist_labels(label_path, num_examples)
    data = list(zip(images, labels))

    # Data is shuffled automatically to distribute classes uniformly.
    for image, label in data:
      yield {
          "image": image,
          "label": label,
      }