Here it is:

        def get_current_scheme():
            scheme = os.name
            if scheme == 'posix':
                scheme = 'posix_prefix'
            return scheme

        def get_current_user_scheme():
            scheme = os.name
            if sys.platform == 'darwin':
                scheme = 'osx_framework_user'
            else:
                scheme += '_user'
            return scheme

What do you think?