def mutable_pair(x,y):
    def get_item(index):
        if index == 0:
            return x
        return y
    def set_item(index , val):
        nonlocal x,y
        if  index == 0:
            x = val
        else:
            y = val

def make_dict():
    contents = None
    def make_rlist(first,rest):
        return (first,rest)

    def dispatch(message,key,value):
        nonlocal contents
        if message == 'push_first':
            contents = make_rlist(mutable_pair(key, value), contents)
z = make_dict()
z('push_first')(2,4)


我有这个问题,当我试图运行此代码时,我得到下一个错误:

Traceback (most recent call last):
File "C:\Users\Michael\workspace\HomeWork1\src\tests.py", line 35, in <module>
z('push_first')(2,4)
TypeError: 'NoneType' object is not callable:


对错误之处的帮助会有所帮助

最佳答案

TypeError:“ NoneType”对象不可调用:


make_dict返回None,因此zNonez('push_first')将不起作用。

09-10 03:04
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