Loads demonstration file and uses it to fill training buffer.
    :param file_path: Location of demonstration file (.demo).
    :param sequence_length: Length of trajectories to fill buffer.
    :return:

def demo_to_buffer(file_path, sequence_length):
    """
    Loads demonstration file and uses it to fill training buffer.
    :param file_path: Location of demonstration file (.demo).
    :param sequence_length: Length of trajectories to fill buffer.
    :return:
    """
    brain_params, brain_infos, _ = load_demonstration(file_path)
    demo_buffer = make_demo_buffer(brain_infos, brain_params, sequence_length)
    return brain_params, demo_buffer