def make_data_object_name(
        dataset_name,
        year, month, day, hour,
        realization, forecast_period):
    """Create a string formatted to give a filename in the MOGREPS dataset."""
    template_string = "prods_op_{}_{:02d}{:02d}{:02d}_{:02d}_{:02d}_{:03d}.nc"
    return template_string.format(
        dataset_name, year, month, day, hour, realization, forecast_period)