def METHOD_NAME():
    group = [
        ("v3", "config_file", "plot_id", {"foo": 1}),
        ("v2", "config_file", "plot_id", {"foo": 2, "bar": 2}),
        ("v1", "config_file", "plot_id", {"baz": 3}),
    ]
    plot_properties = _squash_plots_properties(group)
    assert plot_properties == {"foo": 1, "bar": 2, "baz": 3}