It'd be nice to be able to convert between PSBTv2 and PSBTv0, but this code is commented out. @tcharding, what hurdles did you face when attempting to implement this function in the first place? Looks like it wasn't as straightforward as once imagined?

https://github.com/tcharding/rust-psbt/blob/c32f7547d590c06d93305a51070220fc60142b56/src/v2/mod.rs#L407