Function parse_duration 

pub fn parse_duration(s: &str) -> DateResult<Interval>

Parse an Interval from the text

use interim::{parse_duration, Interval};
use chrono::{Utc, TimeZone};

let now = Utc.with_ymd_and_hms(2022, 9, 17, 13, 27, 0).unwrap();
let week_ago = parse_duration("1 week ago").unwrap();
let minutes = parse_duration("10m").unwrap();

assert_eq!(week_ago, Interval::Days(-7));
assert_eq!(minutes, Interval::Seconds(10*60));