fn parse_request(mut parts: std::str::SplitWhitespace<'_>) -> RequestParserResult<'_> {

        let uri = match parts.next() {

            Some(s) => s,

            None => return Err(RequestParserError::UnexpectedEOF),

        let position = match parts.next() {

            Some(s) => Some(

                s.parse::<SongPosition>()

                    .map_err(|_| RequestParserError::SyntaxError(1, s.to_owned()))?,

            None => None,

        debug_assert!(parts.next().is_none());

        Ok((Request::AddId(uri.to_string(), position), ""))

    }

    fn parse_response(

        parts: ResponseAttributes<'_>,

    ) -> Result<Self::Response, ResponseParserError> {

        let parts: Vec<_> = parts.into();

        let (key, value) = parts.first().ok_or(ResponseParserError::UnexpectedEOF)?;

        debug_assert!(key == &"Id");

        let value = match value {

            GenericResponseValue::Text(value) => value,

                return Err(ResponseParserError::UnexpectedPropertyType("Id", "Binary"))

        let id = value

            .parse()

            .map_err(|_| ResponseParserError::InvalidProperty("Id", value.to_owned()))?;

        Ok(AddIdResponse { id })

    }