Function parse_range 

pub fn parse_range<T>(
    s: &str,
    limits: RangeInclusive<T>,
) -> Result<RangeInclusive<T>>
where
    T: FromStr + Copy + PartialOrd + Display,
    <T as FromStr>::Err: Error + Sync + Send + 'static,

Parse a range from an input string, using values in limits as defaults.

Start and end values must be a type that is parseable from a string. Ranges are inclusive. Whitespace is trimmed from start and end values before parsing.

Valid ranges:

• Range of values (e.g. 1990..2000)
• Range with no upper limit (e.g. 1990..)
• Range with no lower limit (e.g. ..2000)