A small Python URL bruteforce

Hello /prog/, I need help with, well, programming.

I want to bruteforce URLs of the form sys.AAA.org/XXXX/BBB in python and sort the results by success or failure (determined by the returned text). AAA is a given website and BBB a given address.

XXXX is a 1 to 4 characters word using lowercase letters and numbers that I need to bruteforce.

Any tips or example on how to make a very simple bruteforce code in Python, I'm very new to this ?

$ cat > x.py
import string
a = string.digits + string.letters
b = length(a)
for x in range(b**4):
    s = ''.join([a[(x / (b ** i)) % b] for i in range(4)]).reverse()
    url = 'www.AAA.com/%s/BBB' % s
    print('if curl "%s" > /dev/null; then echo %s; fi' % (url,url))

python x.py | bash