Macro try_add 

macro_rules! try_add {
    ($res: expr, $errlog: ident) => { ... };
}

Macro to push_result() and return given ErrorLog if given Result is an Err

Same as #[cfg_attr(tarpaulin, ignore)]

    let mut err_log = ErrorLog::<i32, std::num::ParseIntError>::new();
    match "a1".parse::<i32>() {
        Ok(o) => err_log.set_ok(o),
        Err(e) => {
            err_log.push_err(e);
            return err_log;
        }
    };