class Ascii {
    public static byte[] convert(String s) {
        try {
            if (s != null) {
                return s.getBytes("us-ascii");
            } else {
                return null;
            }
        } catch (UnsupportedEncodingException e) {
            throw new Error(e);
        }
    }

    public static String convert(byte[] b) {<FILL_FUNCTION_BODY>}
}

        try {
            if (b != null) {
                return new String(b, "us-ascii");
            } else {
                return null;
            }
        } catch (UnsupportedEncodingException e) {
            throw new Error(e);
        }
    
<no_super_class>