human
Solve the following python programming problem given the following code:
@ classmethod 
def _accept_conf_filter(cls, confs, unpack_func = None) : 
    def accept_conf_in_item(item) : 
        conf = unpack_func (item) 
        return ((confs is None) or (conf in confs)) 
unpack_func = (cls or (lambda x : x)) 
    return accept_conf_in_item 

    
    

    Fix the buggy line: unpack_func = (cls or (lambda x : x))
assistant
#Here is Python code to fix the buggy line: unpack_func = (cls or (lambda x : x))
.

unpack_func = (unpack_func or (lambda x : x))