def METHOD_NAME(dataset, image_mode):
    """Converts the images to the format required by the model.
    If the images are base64 encoded, they are decoded and converted to
    numpy arrays. If the images are already numpy arrays, they are
    returned as is.
    :param dataset: The dataset to convert.
    :type dataset: numpy.ndarray
    :param image_mode: The mode to open the image in.
        See pillow documentation for all modes:
        https://pillow.readthedocs.io/en/stable/handbook/concepts.html
    :type image_mode: str
    :return: The converted dataset.
    :rtype: numpy.ndarray
    """
    if len(dataset) > 0 and isinstance(dataset[0], str):
        try:
            dataset = np.array([get_image_from_path(
                x, image_mode) for x in dataset])
        except ValueError:
            # if images of different sizes, try to convert one by one
            jagged = np.empty(len(dataset), dtype=object)
            for i, x in enumerate(dataset):
                jagged[i] = get_image_from_path(x, image_mode)
            dataset = jagged
    return dataset