是什麼「__getnewargs__」在此代碼做

Question

class NavigableString(unicode, PageElement): 

    def __new__(cls, value): 
     if isinstance(value, unicode): 
      return unicode.__new__(cls, value) 
     return unicode.__new__(cls, value, DEFAULT_OUTPUT_ENCODING) 

    def __getnewargs__(self):#this line 
     return (NavigableString.__str__(self),) 

Answer 1

試試這個：

x = NavigableString('foop') 
y = pickle.dumps(x) 
z = pickle.loads(y) 
print x, z 

即：__getnewargs__告訴pickle.dumps鹹菜x以這樣的方式，一個pickle.loads從該字符串後面會使用NavigableString.__new__用正確的論據。