Allow annotated variables as lasting only for a bit

expiry.py

import sys
import threading
from time import sleep
from typing import Annotated, get_origin, get_args
from collections import namedtuple


timeout = namedtuple("timeout", "s")


def deleter(seconds, name, scope):
    sleep(seconds)
    exec(f"del {name}", scope.f_globals, scope.f_locals)


class A:
    def __init__(self):
        self.d = {}

    def __setitem__(self, name, val):
        origin = get_origin(val)
        if origin is Annotated:
            *_, deadline = get_args(val)
            if isinstance(deadline, timeout):
                frame = sys._getframe(1)
                threading.Thread(
                    target=deleter,
                    args=(deadline.s, name, frame)
                ).start()
        self.d[name] = val

    def __getitem__(self, item):
        return self.d[item]

__annotations__ = A()

# Usage:

x: Annotated[int, timeout(1)] = 23
print(x)
sleep(2)
print(x)