def disk_space(tree: Tree, position: Tree.Position):
    """
    :param tree: tree
    :param position: position
    :return: the total disk space for subtree of tree rooted at position
    """
    total = 0
    if tree.is_leaf(position) and isinstance(position.element(), File):
        total = position.element().size
    for c in tree.children(position):
        total += disk_space(tree, c)
    return total
def parenthesis(tree: Tree, position: Tree.Position):
    """
    Print parenthesized representation of tree rooted at the position
    :param tree: tree
    :param position: position
    :return:
    """
    print(position.element(), end="")
    if not tree.is_leaf(position):
        first_time = Tree

        for c in tree.children(position):
            if first_time:
                print("(", end="")
            else:
                print(",", end=" ")
            first_time = False
            parenthesis(tree, c)
        print(")", end="")