def METHOD_NAME():
    my_cache = cache.LRUCache[int, Union[int, str]](
        max_cache_items=5,
        expiration_horizon=datetime.timedelta(hours=1),
        retrieval_function=retrieval_function,
    )
    for i in range(5):
        my_cache.put(i)
        assert i in my_cache
    my_cache.clear()
    assert len(my_cache) == 0
    with pytest.raises(KeyError):
        my_cache.get(1, False)