Samples...

gistfile1.py

$ cat teste.py 
#!/usr/bin/env python

import sys

for a in sys.argv:
    print a


$ ./teste.py 1 2 3 4
./teste.py
1
2
3
4

$ cat teste2.py 
#!/usr/bin/env python

import sys

for a in sys.argv[]:
    print a


 ./teste.py 1 2 3 4
  File "./teste.py", line 5
    for a in sys.argv[]:
                      ^
SyntaxError: invalid syntax