sample

    if node_lst[root_index].r_type != 0 and node_lst[root_index].l_type != 0:
        last_huff = HuffmanTree()
        last_huff.right = generate_tree_postorder(node_lst[:-1], root_index - 1)
        skip = #TODO CALL YOUR LENGTH FUNCTION HERE
        last_huff.left = generate_tree_postorder(node_lst[:-skip - 1], root_index - 1 - skip)
        return last_huff
    elif node_lst[root_index].l_type != 0 and node_lst[root_index].r_type == 0:
        last_huff = HuffmanTree()
        last_huff.right = HuffmanTree(node_lst[root_index].r_data)
        last_huff.left = generate_tree_postorder(node_lst[:-1], root_index - 1)
        return last_huff
    elif node_lst[root_index].r_type != 0 and node_lst[root_index].l_type == 0:
        last_huff = HuffmanTree()
        last_huff.left = HuffmanTree(node_lst[root_index].l_data)
        last_huff.right = generate_tree_postorder(node_lst[:-1], root_index - 1)
        return last_huff
    else:
        last_huff = HuffmanTree()
        last_huff.left = HuffmanTree(node_lst[root_index].l_data)
        last_huff.right = HuffmanTree(node_lst[root_index].r_data)
        return last_huff