如何使用add a descriptor在属性获取时捕获并引发TypeError？

class TypeErrorDescriptor:
    def __init__(self, expected_type):
        self.expected_type = expected_type

    def __get__(self, instance, owner):
        if instance is None:
            return self
        raise TypeError(f"Attribute must be of type {self.expected_type}")

    def __set__(self, instance, value):
        if not isinstance(value, self.expected_type):
            raise TypeError(f"Expected {self.expected_type}, got {type(value)}")
        instance.__dict__[self.name] = value

    def __set_name__(self, owner, name):
        self.name = name

class MyClass:
    attr = TypeErrorDescriptor(int)

# 示例使用
obj = MyClass()
try:
    print(obj.attr)  # 这将引发 TypeError
except TypeError as e:
    print(e)

try:
    obj.attr = "not an integer"  # 这也将引发 TypeError
except TypeError as e:
    print(e)

obj.attr = 42  # 这将成功设置属性值
print(obj.attr)  # 输出: 42