pub exec fn ex_hash_map_get<'a, Key, Value, S, Q>(
    m: &'a HashMap<Key, Value, S>,
    k: &Q
) -> result : Option<&'a Value>
where Key: Borrow<Q> + Hash + Eq, Q: Hash + Eq + ?Sized, S: BuildHasher,
Expand description
ensures
obeys_key_model::<Key>() && builds_valid_hashers::<S>()
    ==> match result {
        Some(v) => maps_borrowed_key_to_value(m@, k, *v),
        None => !contains_borrowed_key(m@, k),
    },