def METHOD_NAME(period=3) -> CubeList:
    """Set up a period diagnostic cubes."""
    realizations = [0, 1, 2, 3]
    data = np.full((len(realizations), 2, 2), 0.1, dtype=np.float32)
    times = [datetime(2017, 11, 10, hour) for hour in [3, 6, 9, 12]]
    cubes = CubeList()
    for increment, time in enumerate(times):
        cubes.append(
            set_up_variable_cube(
                data + increment * 0.1,
                name="lwe_thickness_of_precipitation_amount",
                realizations=realizations,
                spatial_grid="equalarea",
                time=time,
                time_bounds=(time - timedelta(hours=period), time),
                frt=datetime(2017, 11, 9, 0),
            )
        )
    return cubes