Importing sys will not be enough to make exit live in the global scope.
exit
You either need to do
from sys import exitexit()
or
import syssys.exit()
Note that, as you are also using argv, in the first case you should do from sys import argv,exit
from sys import argv,exit
You have to apply the function to sys:
because exit is the function itself, you need to call it with ()
()