Just like :meth:`Observable.observed`.

    .. deprecated:: 1.99.1

def observed(func):
    """
    Just like :meth:`Observable.observed`.

    .. deprecated:: 1.99.1
    """

    def wrapper(*args, **kwargs):
        self = args[0]
        assert(isinstance(self, Observable))

        self._notify_method_before(self, func.__name__, args, kwargs)
        res = func(*args, **kwargs)
        self._notify_method_after(self, func.__name__, res, args, kwargs)
        return res

    log.logger.warning("Decorator observable.observed is deprecated:"
                       "use Observable.observed instead")
    return wrapper