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Program To Work with Classes and Methods in Python Assignment Solution.


Write a program to work on methods and classes in python.

Requirements and Specifications

Write a decorator named @class_method that, when used on a function defined within a class (i.e., a def statement nested immediately within a class statement), converts it into a class method, meaning two things.
The method can be called on the class as a whole, rather than on an object of that class.
Whether called on the class as a whole or an object of that class, its first parameter will be the class, rather than an object of that class. In other words, rather than having a self parameter, it has a cls parameter.
Write a class named LimitedString meeting the following requirements.
Constructing a LimitedString requires one positional argument that specifies a maximum length. This maximum length must be a non-negative integer; anything else should cause a ValueError to be raised.
A LimitedString object is a descriptor that can be used to enforce that an object attribute's value is a string, and that its length is no longer than the maximum length.
If an optional keyword argument can_delete is passed when constructing a LimitedString, it controls whether an attribute described by it can be deleted from an object — True if it can, or False if it cannot. (If can_delete, deleting the attribute causes an AttributeError to be raised.)
Source Code
def foo(cls, x, y):
    return cls.__name__, x+y
class LimitedString:
    def __init__(self, length, can_delete = True):
        if not isinstance(length, int):
            raise ValueError
        if length < 0:
            raise ValueError
        self.length = length
        self.can_delete = can_delete
        self.value = None
    def __repr__(self):
        if self.value is None:
            raise AttributeError
        return self.value
    def __set__(self, instance, value):
        if not isinstance(value, str):
            raise ValueError
        if len(value) > self.length:
            raise ValueError
        self.value = value
    def __delete__(self, instance):
        if not self.can_delete:
            raise AttributeError
        self.value = None