Class factory in Python

Question

I\'m new to Python and need some advice implementing the scenario below.

I have two classes for managing domains at two different registrars. Both have the same inte

Answer 1

Here a metaclass implicitly collects Registars Classes in an ENTITIES dict

class DomainMeta(type):
    ENTITIES = {}

    def __new__(cls, name, bases, attrs):
        cls = type.__new__(cls, name, bases, attrs)
        try:
            entity = attrs['domain']
            cls.ENTITIES[entity] = cls
        except KeyError:
            pass
        return cls

class Domain(metaclass=DomainMeta):
    @classmethod
    def factory(cls, domain):
        return DomainMeta.ENTITIES[domain]()

class RegistrarA(Domain):
    domain = 'test.com'
    def lookup(self):
        return 'Custom command for .com TLD'

class RegistrarB(Domain):
    domain = 'test.biz'
    def lookup(self):
        return 'Custom command for .biz TLD'


com = Domain.factory('test.com')
type(com)       # 
com.lookup()    # 'Custom command for .com TLD'

com = Domain.factory('test.biz')
type(com)       # 
com.lookup()    # 'Custom command for .biz TLD'