Python 绝对路径写法

Python 绝对路径写法
下面代码目录结构：
./app/service/file.py
./media

import os 
from os import path
basedir = path.dirname(path.dirname(path.dirname(path.abspath(__file__))))
if not  path.exists(path.join(basedir, 'media')):
	os.mkdir(path.join(basedir, 'media'))
file_path_new = path.join(basedir,'media/'+file_name)