Adds to decorated class __getter__ and __setter__ methods that allow to access attributes from proxy_object in the parent class

proxy_obj.py

import inspect


def proxy_to(proxy_obj_name, fields):
    # type: (Text, List[Text]) -> Callable
    """
    Adds to decorated class __getter__ and __setter__ methods that allow to access
    attributes from proxy_object in the parent class

    :param proxy_obj_name: The name of the proxy object that has decorated class.
    :param fields:
        Fields which should be accessible in parent object from the proxy object.
    """

    def __getattr__(self, name):
        if name in fields:
            proxy_obj = getattr(self, proxy_obj_name)
            return getattr(proxy_obj, name)
        module_with_class = "{}::{}".format(
            inspect.getfile(self.__class__), self.__class__.__name__
        )
        raise AttributeError("{} has not attr `{}`".format(module_with_class, name))

    def __setattr__(self, key, value):
        if key in fields:
            proxy_obj = getattr(self, proxy_obj_name)
            setattr(proxy_obj, key, value)
        else:
            super(self.__class__, self).__setattr__(key, value)

    def dec(cls):
        cls.__getattr__ = __getattr__
        cls.__setattr__ = __setattr__
        return cls

    return dec