OrdMap::range panics / includes items outside of requested range

[theli-ua]

use im::OrdMap;

fn main() {
    let mut m = OrdMap::default();
    m.insert(1, ());
    m.insert(3, ());
    assert_eq!(1, m.range(1..2).collect::<Vec<_>>().len());
}

thread 'main' panicked at 'assertion failed: `(left == right)`
  left: `1`,
 right: `2`', src/main.rs:7:5

If you specify an end beyond whats in the tree it simply panics