async def METHOD_NAME(
    bucket_fs: BucketFS, mock_bucket_provider: MockBucketProvider
) -> None:
    assert await bucket_fs.exists(PurePosixPath("/"))
    assert await bucket_fs.exists(PurePosixPath(""))
    assert not await bucket_fs.exists(PurePosixPath("some_key"))
    assert not await bucket_fs.exists(PurePosixPath("some_key/foo"))
    await mock_bucket_provider.put_blob("some_key/foo", b"data")
    assert await bucket_fs.exists(PurePosixPath("some_key/foo"))
    assert await bucket_fs.exists(PurePosixPath("some_key"))
    assert not await bucket_fs.exists(PurePosixPath("some_key/foo/bar"))