def extend_list(val, lst=[]):
    lst.append(val)
    return lst

list1 = extend_list(10)
list2 = extend_list(123, [])
list3 = extend_list('a')

print("list1 =", list1)
print("list2 =", list2)
print("list3 =", list3)

def extend_list(val, lst=None):
    if lst is None:
        lst = []
    lst.append(val)
    return lst

import sys
import types

# Создаём фейковый модуль
fake = types.SimpleNamespace()
fake.get_data = lambda: "подмена работает"

# Подменяем импорт
sys.modules['external_service'] = fake

# Теперь даже import будет работать
import external_service
print(external_service.get_data())  # → "подмена работает"

import asyncio
import time
from collections import OrderedDict
from typing import Any, Optional
import threading

class AsyncTTLCache:
    def __init__(self, maxsize: int = 1024, ttl: int = 60):
        self._cache = OrderedDict()
        self._maxsize = maxsize
        self._ttl = ttl
        self._lock = threading.Lock()
        self._cleanup_task = asyncio.create_task(self._cleanup_expired())

    async def get(self, key: str) -> Optional[Any]:
        with self._lock:
            if key not in self._cache:
                return None
            value, expiry = self._cache[key]
            if time.time() > expiry:
                del self._cache[key]
                return None
            # Move to end to mark as recently used
            self._cache.move_to_end(key)
            return value

    async def set(self, key: str, value: Any) -> None:
        with self._lock:
            if key in self._cache:
                self._cache.move_to_end(key)
            self._cache[key] = (value, time.time() + self._ttl)
            if len(self._cache) > self._maxsize:
                self._cache.popitem(last=False)

    async def invalidate(self, key: str) -> None:
        with self._lock:
            if key in self._cache:
                del self._cache[key]

    async def _cleanup_expired(self) -> None:
        while True:
            await asyncio.sleep(self._ttl)
            with self._lock:
                now = time.time()
                expired_keys = [
                    k for k, (_, expiry) in self._cache.items()
                    if expiry <= now
                ]
                for k in expired_keys:
                    del self._cache[k]

    def __del__(self):
        self._cleanup_task.cancel()


# Пример использования
async def main():
    cache = AsyncTTLCache(ttl=2)
    
    await cache.set("a", 1)
    print(await cache.get("a"))  # 1
    
    await asyncio.sleep(3)
    print(await cache.get("a"))  # None
    
    await cache.set("b", 2)
    await cache.invalidate("b")
    print(await cache.get("b"))  # None

asyncio.run(main())