def __call__(self, *args, **kwargs):
        """calls call_back function with path, args, kwargs override in descendants for any special handling"""
        return self._call_back(self._path, *args, **kwargs)
def __call__ ( self , * args , ** kwargs ) : return self . _call_back ( self . _path , * args , ** kwargs )
calls call_back function with path, args, kwargs override in descendants for any special handling