@register.filter
def is_parent_of(page1, page2):

    try:
        return page1.tree_id == page2.tree_id and page1.lft < page2.lft and page1.rght > page2.rght
    except AttributeError:
        return False

# ------------------------------------------------------------------------
Determines whether a given page is the parent of another page
dataset/ETHPy150Open django-leonardo/django-leonardo/leonardo/module/nav/templatetags/webcms_nav_tags.py/is_parent_of