AttributeError: 'NoneType' object has no attribute 'n' in list of class objects

[jdrp]

So, I was trying to develop a game in PyGame and came across a problem. I tried it it on a much simpler code and it still returns an error, so I think it's not about my big code. Here's what goes wrong (the short version)

from random import randint as rand

def A():
    def __init__(self):
        self.n = rand(1,10)

b = []
for i in range(10):
    b.append(A())
for i in range(10):
    print(str(b[i].n))

So, basically, I'm filling "b" with a list of 10 "a" objects. Each object gets assigned a random value on its __init__. Then I iterate through all the objects printing their "n" value. Well, instead of printing some random numbers, it gives me an error:

Error:
Traceback (most recent call last):
  File "C:/Users/sergio/Desktop/python/test/d.py", line 11, in <module>
    print(str(b[i].n))
AttributeError: 'NoneType' object has no attribute 'n'

Any help would be appreciated.