How to import whole namespace into global symbol table? (newbie)

[Scott Simpson]

Suppose I have the following python program:

def func():
     from sys import stderr, exit
     try:
         f = open("foo", 'r')
     except IOError:
         print >> stderr, "Input file foo does not exist"
         exit(1)

def main():
     import sys

     if len(args) != 0:
         sys.exit(1)

     func()

if __name__ == '__main__':
     main()

Notice that I have two "import sys" statements, one for each function. 
Is there any way to import the "sys" stuff to the global symbol table so 
I don't need two "import" statements?

Lastly, is there an equivalent of Perl's "die" function? I'm writing to 
stderr and dieing above but I'm not quite sure if this is the "correct" way.