运行的时候为什么老是报 name “os” is not defined 呢，都 import os了呀，请指教，谢谢

[sunshine16817]

Traceback (most recent call last):
File "main.py", line 48, in
flags.DEFINE_string("emb_file", "wiki_100.utf8", "Path for pre_trained embedding")
NameError: name 'os' is not defined