Python help! How to make a static, yet dynamic, property in a base class?

1_problem.py

SERVICE_ID_TACO_BELL = 1
SERVICE_ID_T_MOBILE = 2
SERVICE_NAMES = {
    SERVICE_ID_TACO_BELL: "Taco Bell",
    SERVICE_ID_T_MOBILE: "T-Mobile",
}


class BaseService(object):
    service_id = None

    @classmethod
    def get_service_name(cls):
        return SERVICE_NAMES.get(cls.service_id)


class TacoBell(BaseService):
    service_id = SERVICE_ID_TACO_BELL


# Right now we can do this:
assert TacoBell.service_id == SERVICE_ID_TACO_BELL
assert TacoBell.get_service_name() == "Taco Bell"

# The goal is to be able to do this:
assert TacoBell.service_name == "Taco Bell"

# We can do something like this after the fact:
setattr(TacoBell, 'service_name', TacoBell.get_service_name())
# but that feels messy

# How can we add a static, yet dynamic property to
# `BaseService` that checks the subclass's `service_id`
# property against SERVICE_NAMES to return the value?

2_solution_with_metaclass.py

SERVICE_ID_TACO_BELL = 1
SERVICE_ID_T_MOBILE = 2
SERVICE_NAMES = {
    SERVICE_ID_TACO_BELL: "Taco Bell",
    SERVICE_ID_T_MOBILE: "T-Mobile",
}

class ServiceMetaClass(type):
    def __init__(cls, *args, **kwargs):
        type.__init__(cls, *args, **kwargs)
        cls.service_name = cls.get_service_name()


class BaseService(object):
    __metaclass__ = ServiceMetaClass

    service_id = None

    @classmethod
    def get_service_name(cls):
        return SERVICE_NAMES.get(cls.service_id)


class TacoBell(BaseService):
    service_id = SERVICE_ID_TACO_BELL


# All things go
assert TacoBell.service_id == SERVICE_ID_TACO_BELL
assert TacoBell.get_service_name() == "Taco Bell"
assert TacoBell.service_name == "Taco Bell"