code: def observed(func):
      
  
      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
docs: Just like :meth:`Observable.observed`.
  
      .. deprecated:: 1.99.1