def get_next_page_count(value):
    """
    Expects ``value`` to be an instance of ``Paginator.Page``.

    Returns the number of items on the next page, if any; does not check
    for the existence of the next page.
    """
    p = value.paginator.page(value.next_page_number())

    return p.end_index() - p.start_index() + 1