How to Build a TTL Cache Dict in Python

import time

class TTLDict(dict):
    def __init__(self, ttl, *args, **kwargs):
        self.ttl = ttl
        self._expires = {}
        super().__init__(*args, **kwargs)

    def __setitem__(self, key, value):
        super().__setitem__(key, value)
        self._expires[key] = time.time() + self.ttl

    def __getitem__(self, key):
        if self._is_expired(key):
            self._delete_expired(key)
            raise KeyError(key)
        return super().__getitem__(key)

    def __contains__(self, key):
        if self._is_expired(key):
            self._delete_expired(key)
            return False
        return super().__contains__(key)

    def get(self, key, default=None):
        try:
            return self[key]
        except KeyError:
            return default

    def _is_expired(self, key):
        return key in self._expires and time.time() > self._expires[key]

    def _delete_expired(self, key):
        del dict.__getitem__(self, key)
        del dict.__getattribute__(self, '_expires')[key]

if __name__ == "__main__":
    cache = TTLDict(2)
    cache["name"] = "Alice"
    print(f"immediate: {cache.get('name')}")
    time.sleep(3)
    print(f"after 3s: {cache.get('name')}")
    print(f"in dict: {'name' in cache}")