fn test_basic_op<T>(a: &af::Array<T>)
where
    // T: af::Fromf64 + af::HasAfEnum + ???
{
    println!("Element-wise arithmetic");
    let b = af::add(&af::sin(a), &T::fromf64(1.5f64), false);

    let b2 = af::add(&af::sin(a), &af::cos(a), false);

    let b3 = !a;
    af::af_print!("sin(a) + 1.5 => ", b);
    af::af_print!("sin(a) + cos(a) => ", b2);
    af::af_print!("!a => ", b3);

    let a_plus_b = a.clone() + b.clone();
    af::af_print!("a + b", a_plus_b);

    let minus_a = -(a.clone());
    af::af_print!("-a ", minus_a);
}

fn test_basic_op<T>(a: &af::Array<T>)
where
    T: af::HasAfEnum<UnaryOutType = T>
        + af::Fromf64
        + af::Convertable<OutType = T>
        + af::ImplicitPromote<T, Output = T>,
    af::Array<T>: std::ops::Neg<Output = af::Array<T>>,
{
    ...
}