pub fn global_pos_with_spaces<'store, T, NS, It: Iterator>(
    root: T::TreeId,
    no_spaces: &mut It,
    node_store: &'store NS
) -> (Vec<It::Item>,)where
    It::Item: Clone + PrimInt,
    T::TreeId: Clone,
    NS: 'store + NodeStore<T::TreeId, R<'store> = T>,
    T: Tree<ChildIdx = It::Item> + WithStats,