def tree_merge(node1, node2):
    res = None
    if node1 is None:
        res = node2
        res.goodsid = '-1'
        res.name = str(node2.depths) + '-' + str(node2.order_index)
        res.parent=node2.parent
        return res
    if node2 is None:
        res = node1
        res.goodsid = '-1'
        res.name = str(node1.depths) + '-' + str(node1.order_index)
        res.parent=node1.parent
        return res
    res=node1
    res.cart += node2.cart
    res.visit_cnt += node2.visit_cnt
    res.goodsid = '-1'
    children_1 = list(node1.children)
    children_2 = list(node2.children)
    children_1,children_2=list_extend(children_1,children_2)
    tmp_children=[]
    for i,j in zip(children_1,children_2):
        tmp_children.append(tree_merge(i,j))
    res.children=tmp_children
    return  res