using function associated with a struct as a parameter

[ericqu]

Hi, I'm new here (I hope I posted in the right area).
I'm not sure how to pass a function as a parameter when that function is associated with a struct.
I have seen in the example how to do that when it is not associated with a struct, but it seems neater to do that with struct as well.
I use the benchmark in the example to illustrate this, but ideally, I want to do that generally, I don't need to do that at runtime but at compile time.

The below code errors at: _ = il.func() because func() is not defined in the struct. What would be the proper way to achieve that?

import benchmark

struct Illustration:
    var element :UInt8
    fn __init__(inout self) -> None:
        self.element = UInt8.MAX
    
    fn option_one(inout self) -> None:
        self.element = 1
    
    fn option_two(inout self) -> None:
        self.element = 2

    @staticmethod
    fn bench[func: fn(inout self: Illustration) -> None]():

        print('in bench')
            
        @parameter
        fn test_fn():
            var il = Self()
            _ = il.func()

        var secs = benchmark.run[test_fn](max_runtime_secs=1).mean()

        print('bench done in ', secs)

fn main():
    Illustration.bench[Illustration.option_one]