fn new() -> Self {
        List {
            arena: Arena::new(),
            head: NULL,
            tail: NULL,
        }
    }
/// Constructs a new, empty doubly linked list.
Constructs a new, empty doubly linked list.
Constructs a new empty doubly linked list .
fn new() -> Self {
        List {
            arena: Arena::new(),
            head: NULL,
            tail: NULL,
        }
    }
fn new ( ) -> Self { List { arena : Arena :: new ( ) , head : NULL , tail : NULL , } }
Constructs a new, empty doubly linked list.
Constructs a new empty doubly linked list .