# ------------ magic.py
# W MySettings piszemy sobie defaulty. Zostaną one nadpisane przez to co jest w module settings.

import settings

class MetaSettings(type):
   def __new__(cls, name, bases, attrs):
      # tu nadpisywanie
      attrs.update(settings.__dict__)
      return type.__new__(cls, name, bases, attrs)

class MySettings(object):
   __metaclass__ = MetaSettings
   FOO = 'myfoo'

assert MySettings.FOO == 'myfoo' # bo nie będzie nadpisane
assert MySettings.BAR == 'bar'

# (ciach) ----------- settings.py

BAR = 'bar'