Function for_each_year_in_search_space 

fn for_each_year_in_search_space<F>(
    search_space: &str,
    agent: &Agent,
    commodity_id: &CommodityID,
    years: &[u32],
    processes: &ProcessMap,
    producers: &HashMap<(CommodityID, RegionID, u32), Rc<Vec<Rc<Process>>>>,
    f: F,
) -> Result<()>
where
    F: FnMut(CommodityID, RegionID, u32, Rc<Vec<Rc<Process>>>) -> Result<()>,

Parse the search space string and iterate over the processed search space for each year