def METHOD_NAME(labelled_flows):
    out = labelled_flows.to_geojson_string()
    dict = loads(out)
    assert all(
        test in dict["features"][0]["properties"]["outflows"].keys()
        for test in ["Smart", "Feature"]
    )
    assert (
        "524 1 01 04" in dict["features"][0]["properties"]["outflows"]["Feature"].keys()
    )
    assert all(
        test in dict["features"][0]["properties"]["inflows"].keys()
        for test in ["Smart", "Feature"]
    )
    assert (
        "524 3 08 43" in dict["features"][0]["properties"]["inflows"]["Feature"].keys()
    )
    assert dict["features"][0]["properties"]["inflows"]["Feature"]["524 3 08 43"] == 5