···2020 // unwrap: this can never fail
2121 let child_in = child.stdin.as_mut().unwrap();
2222 for item in input.into_iter() {
2323- write!(child_in, "{}\n", item.to_string())?;
2323+ write!(child_in, "{item}\n")?;
2424 }
2525 let output = child.wait_with_output()?;
2626 if output.stdout.is_empty() {