Python class variable update

class MyClass(object):
    next_number = 0

    def __init__(self):
        self.number = self.next_number
        MyClass.next_number += 1

class MyClassA(MyClass):
    pass

Above it would appear I am forced hardcode the class name when updating the class variable on line 6 since writing:

self.__class__.next_number += 1

results in a new class variable in any derived class. Is there any alternative to hardcoding the class name?

Also on line 5 should I instead write:

self.number = self.__class__.next_number

to make it obvious next_number is a class variable.