def METHOD_NAME(period):
    """Return multi-realization rain and sleet cubes as a tuple. This fixture
    is parameterised such that any test using it will be run with both
    instantaneous and period diagnostics."""
    rain, sleet = precipitation_cubes(period)
    rain = add_coordinate(rain, [0, 1], "realization", coord_units=1, dtype=np.int32)
    sleet = add_coordinate(sleet, [0, 1], "realization", coord_units=1, dtype=np.int32)
    # Modify one realization to demonstrate that the implicit realization collapse
    # within the plugin is giving the expected results; these are provided by the
    # expected_probabilities_multi_realization fixture below.
    rain.data[1, 1] = np.full_like(rain.data[1, 1], 0.6)
    return rain, sleet