Function qip::common_circuits::work_on

pub fn work_on<F>(
    b: &mut dyn UnitaryBuilder, 
    r: Register, 
    indices: &[u64], 
    f: F
) -> Result<Register, CircuitError> where
    F: Fn(&mut dyn UnitaryBuilder, Vec<Register>) -> Result<Vec<Register>, CircuitError>, 

Extract a set of indices, provide them to a function, then reinsert them in the correct order.