sample

    if root_index < 0:
        root_index += len(node_lst)
    if node_lst[root_index].r_type != 0 and node_lst[root_index].l_type != 0:
        last_huff = HuffmanTree(None, None, generate_tree_postorder(node_lst[:len(node_lst)-1], root_index - 1))
        index_jump = num_nodes_int(last_huff.right)
        last_huff.left = generate_tree_postorder(node_lst[:len(node_lst) - index_jump - 1], root_index - 1 - index_jump)
        return last_huff
    elif node_lst[root_index].l_type != 0 and node_lst[root_index].r_type == 0:
        return HuffmanTree(None, generate_tree_postorder(node_lst[:len(node_lst)-1], root_index - 1),  HuffmanTree(node_lst[root_index].r_data))
    elif node_lst[root_index].r_type != 0 and node_lst[root_index].l_type == 0:
        return HuffmanTree(None, HuffmanTree(node_lst[root_index].l_data), generate_tree_postorder(node_lst[:len(node_lst)-1], root_index - 1))
    else:
        return HuffmanTree(None, HuffmanTree(node_lst[root_index].l_data), HuffmanTree(node_lst[root_index].r_data))