Idea for class based settings.

settings.__init__.py

from .local import config


config.render(globals())

settings.base.py

import string


class late_bound(object):
    def __init__(self, getter):
        self.getter = getter

    def __get__(self, instance, owner):
        return self.getter(instance)


class BaseConfig(object):
    DEBUG = False

    @late_bound
    def TEMPLATE_DEBUG(self):
        return self.DEBUG

    def __setattr__(self, name, value):
        self.__dict__[name] = value

    def __delattr__(self, name):
        del self.__dict__[name]

    def render(self, namespace):
        namespace.clear()
        for k in dir(self):
            if not (set(k) - set(string.ascii_uppercase + '_') or k.startswith('_')):
                namespace[k] = getattr(self, k)
        return namespace

settings.dev.py

from .base import BaseConfig


class DevConfig(BaseConfig):
    DEBUG = True

settings.local.py

from .dev import DevConfig


config = DevConfig()

test.py

from pprint import pprint

import settings


if __name__ == '__main__':
    pprint(settings.__dict__)