print_contents(w, "+", contents, encoding)?;

                let sign = if let PrintableAtom::Edges(ref e) = change {
                    if e[0].flag.deleted {
                        "-"
                    } else {
                        "+"
                    }
                } else {
                    "+"
                };
                print_contents(w, sign, contents, encoding)?;

    let (i, contents) = parse_contents('+', encoding.clone(), i)?;

    let (i, contents) = if let Ok(s) = parse_contents('+', encoding.clone(), i) {
        s
    } else {
        parse_contents('-', encoding.clone(), i)?
    };

        Ok((i, vec))
    } else {
        Err(nom::Err::Error(nom::error::Error::new(
            i,
            nom::error::ErrorKind::Verify,
        )))

        if !vec.is_empty() {
            return Ok((i, vec))
        }

    Err(nom::Err::Error(nom::error::Error::new(
        i,
        nom::error::ErrorKind::Verify,
    )))