python password generator

import random
import __future__

a = 'abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWYXZ23456789$%&()=?+#-}][{*/:<>~' #0Ol1!I
b = 'abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWYXZ23456789'
d = 'abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWYXZ23456789@#%_-&*()'
all = "".join((chr(i) for i in range(33,127)))

def doa(l = 20, chars = a):
    return "".join(chars[int(random.random() * (len(chars[:-1])+1))] for i in range(l))

for i in range(4):
    print(20-i, ':', doa(20 - i, all))
    print(20-i, ':', doa(20 - i, all))
    print(20-i, ':', doa(20 - i, all), "\n")

print('username:', doa(10, b), "\n")
print('16 readable:', doa(16, d), "\n")