[yz@test-4 ~]$ python -m pdb /home/yz/test.py
> /home/yz/test.py(11)<module>()
-> from __future__ import print_function
(Pdb) l
11  ->	from __future__ import print_function
12  	import sys
13  	import os
14  	import platform
(Pdb) n
> /home/yz/test.py(12)<module>()
-> import sys
……
> /home/yz/test.py(17)<module>()
-> g_sc_os_vers = None
(Pdb) p g_sc_os_vers
None