problem with "hiding" object

[league55]

This is code that's supposed to generate a cipher once, then prevent the cipher from being altered or viewed, but the code doesn't work. What's wrong with it?

from cryptography.fernet import Fernet


class Cipher:

    def __init__(self, value=None):
        self.cipher = Fernet(Fernet.generate_key())

    @property
    def cipher(self):
        return self.__cipher

    @cipher.setter
    def cipher(self, value=None):
        if not self.__cipher:
            self.__init__()
        else:
            raise ValueError("Cipher may not be altered.")

    def __repr__(self):
        return "Cipher may not be viewed."

[buran]

the code doesn't work.

how exactly doesn't work? Show us how you run it, i.e. how you instantiate object of class Cipher.
If you get ant error, post the full traceback in error tags.

[league55]

Here is the instantiation:

cipher = Cipher()

And here's the error message:

Output:
Traceback (most recent call last):
  File "C:\Users\leagu\pythonprojects\costcontrol\classes\keyclass.py", line 25, in <module>
    cipher = Cipher(data)
  File "C:\Users\leagu\pythonprojects\costcontrol\classes\keyclass.py", line 7, in __init__
    self.cipher = value
  File "C:\Users\leagu\pythonprojects\costcontrol\classes\keyclass.py", line 15, in cipher
    if self.cipher != None:
  File "C:\Users\leagu\pythonprojects\costcontrol\classes\keyclass.py", line 11, in cipher
    return self.__cipher
AttributeError: 'Cipher' object has no attribute '_Cipher__cipher'

[wavic]

Why do you name the attribute and the methods with the same name?

[league55]

I found out from other sources that, in Python, you can't protect an object's attributes, so what I'm trying to do won't work. Thanks for your time.