#!/usr/bin/env python3

class Test():

    instances = []

    def __init__(self, name):
        self.name = name
        self.register(self)
        #vagy legyen inkább: self.__class__.register(self) ?


    @classmethod
    def register(cls,instance):
        cls.instances.append(instance)

    @classmethod
    def kill(cls,name):
        for instance in cls.instances:
            if instance.name == name:
                cls.instances.remove(instance)

    @classmethod
    def print_instances(cls):
        for instance in cls.instances:
            print(instance, instance.name)

for name in ['Alpha', 'Beta', 'Gamma']:
    Test(name)

Test.print_instances()

Test.kill('Alpha')

Test.print_instances()