You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: anplusb.rs
    path of file: ./repos/gosub-engine/crates/gosub_css3/src/parser
    
    the code of the file until where you have to start completion: use crate::node::{Node, NodeType};
    
    fn anplusb() {
        test!(
            parse_anplusb,
            "1n+2",
            Box::new(NodeType::AnPlusB {
                a: "1".to_string(),
                b: "2".to_string()
            })
        );
        test!(
            parse_anplusb,
            "1n-2",
            Box::new(NodeType::AnPlusB {
                a: "1".to_string(),
                b: "-2".to_string()
            })
        );
        test!(
            parse_anplusb,
            "-1n+2",
            Box::new(NodeType::AnPlusB {
                a: "-1".to_string(),
                b: "2".to_string()
            })
        );
        test!(
            parse_anplusb,
            "-1n-20",
            Box::new(NodeType::AnPlusB {
                a: "-1".to_string(),
                b: "-20".to_string()
            })
        );
        test!(
            parse_anplusb,
            "-1n+20",
            Box::new(NodeType::AnPlusB {
                a: "-1".to_string(),
                b: "20".to_string()
            })
        );
        test!(
            parse_anplusb,
            "1n",
            Box::new(NodeType::AnPlusB {
                a: "1".to_string(),
                b: "0".to_string()
            })
        );
        test!(
            parse_anplusb,
            "10n-5",
            Box::new(NodeType::AnPlusB {
                a: "10".to_string(),
                b: "-5".to_string()
            })
        );
        test!(
            parse_anplusb,
            "0n+5",
            Box::new(NodeType::AnPlusB {
                a: "0".to_string(),
                b: "5".to_string()
            })
        );
        test!(
            parse_anplusb,
            "1n+0",
            Box::new(NodeType::AnPlusB {
                a: "1".to_string(),
                b: "0".to_string()
            })
        );
        test!(
            parse_anplusb,
            "n+0",
            Box::new(NodeType::AnPlusB {
                a: "1".to_string(),
                b: "0".to_string()
            })
        );
        test!(
            parse_anplusb,
            "n",
            Box::new(NodeType::AnPlusB {
                a: "1".to_string(),
                b: "0".to_string()
            })
        );
        test!(
            parse_anplusb,
            "2n+0",
            Box::new(NodeType::AnPlusB {
                a: "2".to_string(),
                b: "0".to_string()
            })
        );
        test!(
            parse_anplusb,
            "2n",
            Box::new(NodeType::AnPlusB {
                a: "2".to_string(),
                b: "0".to_string()
            })
        );
        test!(
            parse_anplusb,
            "3n-6",
            Box::new(NodeType::AnPlusB {
                a: "3".to_string(),
                b: "-6".to_string()
            })
        );
        test!(
            parse_anplusb,
            "3n + 1",
            Box::new(NodeType::AnPlusB {
                a: "3".to_string(),
                b: "1".to_string()
            })
        );
        test!(
            parse_anplusb,
            "+3n - 2",
            Box::new(NodeType::AnPlusB {
                a: "3".to_string(),
                b: "-2".to_string()
            })
        );
        test!(
            parse_anplusb,
            "-n+ 6",
            Box::new(NodeType::AnPlusB {
                a: "-1".to_string(),
                b: "6".to_string()
            })
        );
        test!(
            parse_anplusb,
            "-n+6",
            Box::new(NodeType::AnPlusB {
                a: "-1".to_string(),
                b: "6".to_string()
            })
        );
        test!(
            parse_anplusb,
            "-n +6",
            Box::new(NodeType::AnPlusB {
                a: "-1".to_string(),
                b: "6".to_string()
            })
        );
    }