Function int_val_parser_opt 

pub fn int_val_parser_opt<T>(
    data: &mut HashMap<String, Option<String>>,
    key: &'static str,
) -> Result<Option<T>, Ts3Error>
where
    T: FromStr<Err = ParseIntError>,

Helper function to retrieve and parse value from line-hashmap, (re)moves value.

use ts3_query::*;
use std::collections::HashMap;

let mut v: HashMap<String, Option<String>> =
    vec![("abc".to_string(), Some("123".to_string())),
    ("def".to_string(), None)]
    .into_iter().collect();
assert_eq!(Some(123),raw::int_val_parser_opt::<i32>(&mut v, "abc").unwrap());
assert_eq!(None,raw::int_val_parser_opt::<i32>(&mut v, "def").unwrap());