pub trait InsertMut<K, V>: CollectionMut {
type Output;
fn insert(&mut self, key: K, element: V) -> Self::Output;
}
impl<'a, K, V, S> InsertMut<K, V> for HashMap<K, V, S> where
K: Eq + Hash,
S: BuildHasher, type Output = Option<V>;
impl<'a, K, V> InsertMut<K, V> for BTreeMap<K, V> where
K: Eq + Ord, type Output = Option<V>;
impl<T> InsertMut<usize, T> for LinkedList<T> type Output = ();
impl InsertMut<usize, char> for String type Output = ();
impl<T> InsertMut<usize, T> for Vec<T> type Output = ();