def METHOD_NAME():
    group_1 = compose.Select("a", "b") | preprocessing.OneHotEncoder()
    group_2 = compose.Select("x", "y")
    product = group_1 + group_2 + group_1 * group_2
    assert product.transform_one(dict(a=1, b=2, x=4, y=4, z=5)) == {
        "a_1*x": 4,
        "a_1*y": 4,
        "b_2*x": 4,
        "b_2*y": 4,
        "x": 4,
        "y": 4,
        "a_1": 1,
        "b_2": 1,
    }