def METHOD_NAME() -> None:
    mock_file = mock.Mock()
    opener = mock.Mock(spec=open, return_value=mock_file)
    cache: dict = {}
    manager = CachingFileManager(opener, "filename", cache=cache)
    manager.acquire()
    assert len(cache) == 1
    manager2 = CachingFileManager(opener, "filename", cache=cache)
    manager2.acquire()
    assert len(cache) == 2
    with set_options(warn_for_unclosed_files=False):
        del manager
        gc.collect()
    assert len(cache) == 1
    with set_options(warn_for_unclosed_files=False):
        del manager2
        gc.collect()
    assert not cache