如何将nom take_while和is_digit用于字符串输入(&S)

[dependencies]
nom = "6.2.1"

use nom::character::complete::{digit1, multispace0};
use nom::combinator::recognize;
use nom::sequence::pair;
use nom::IResult;

fn parse_input(input: &str) -> IResult<&str, &str> {
    pair(
        recognize(multispace0),
        recognize(digit1)
    )(input)
}

fn main() {
    let input = "   123abc";
    match parse_input(input) {
        Ok((remaining, parsed)) => {
            println!("解析成功！剩余部分：{}", remaining);
            println!("解析结果：{}", parsed);
        }
        Err(err) => {
            println!("解析失败：{}", err);
        }
    }
}