import random

def genvalue():
    return random.randint(1, 100)

class A(object):
    def __init__(self, x = genvalue()):
        self.x = x

class B(A):
    def __init__(self):
        super(B, self).__init__()

t1 = A(10)
t2 = B()
t3 = B()

print t1.x
print t2.x
print t3.x

class A(object):
    def __init__(self, x=None):
        if x is None:
            self.x = genvalue()