Metaclass example

meta.py

import os

class DebianPackagerMixin:
    def boo(self):
        print('debian')

class RedhatPackagerMixin:
    def boo(self):
        print('redhat')

class DefaultPackage:
    def boo(self):
        print('default')


class BasePackage(type):

    def __new__(meta, name, bases, dct):
        if os.path.isfile("/etc/debian_version"):
                bases += (DebianPackagerMixin, )
        elif os.path.isfile("/etc/redhat-release"):
                bases += (RedhatPackagerMixin, )
        else:
            bases += (DefaultPackage,)
        return super(BasePackage, meta).__new__(meta, name, bases, dct)


class Package(object):
    __metaclass__ = BasePackage
    
    # common stuff here

if __name__ == '__main__':

    p = Package()
    p.boo()