use std::cmp::Ordering;
use super::Collection;
/// Implements an interface for collections that can be sorted.
///
/// A collection that implements this trait must
/// be able to re-order its elements in a specific order (sorting).
pub trait Sortable: Collection {
fn sort<F>(&mut self, f: F) where F: FnMut(&Self::Item, &Self::Item) -> Ordering;
}