Python-сообщество

from abc import ABCMeta, abstractmethod
class Basic(object):
    __metaclass__ = ABCMeta
    
    allInstances = set()
    nextId = 1
    
    def __init__(self, name):
        self.name = name
        self.idNumber = self.__class__.nextId
        self.__class__.nextId += 1
        self.allInstances.add(self)
    def __del__(self):
        self.allInstances.remove(self)
        
    
    @property
    def idNumber(self):
        return self._idNumber
    @idNumber.setter
    def idNumber(self, value):
        self._idNumber = value
        
    @property
    def name(self):
        return self._name
    @name.setter
    def name(self, value):
        self._name = value
        
        
class Child1(Basic):
    pass
class Child2(Basic):*
    pass
    

>>> from Basic import *
>>> child1_instance1 = Child1("child1_instance1")
>>> child1_instance2 = Child1("child1_instance2")
>>> child1_instance2 = Child2("child1_instance2")
>>> child2_instance2 = Child2("child2_instance2")

for i in child1_instance1.allInstances:
    print i.name
    print i.idNumber

>>> for i in child1_instance1.allInstances:
...     print i.name
...     print i.idNumber
... 
child1_instance1
1
child1_instance2
2
child2_instance2
2
child1_instance2
1

from abc import ABCMeta
class MyMeta(ABCMeta):
    def __init__(cls, name, bases, dct):
        super(MyMeta, cls).__init__(name, bases, dct)
        cls.allInstances = set()

self.idNumber = self.__class__.nextId
self.__class__.nextId += 1