from __future__ import annotations

from typing import Optional


class CacheBase:
    """缓存接口"""

    def get(self, key: str) -> Optional[str]:
        raise NotImplementedError

    def set(self, key: str, value: str, ttl: int) -> None:
        raise NotImplementedError


class NoopCache(CacheBase):
    """空实现缓存"""

    def get(self, key: str) -> Optional[str]:
        return None

    def set(self, key: str, value: str, ttl: int) -> None:
        return None