def METHOD_NAME(self) -> Tuple[ROIInfo, Optional[np.ndarray]]:
    self.arrays.seek(0)
    seg = np.load(self.arrays)
    self.arrays.seek(0)
    alternative = {name: array for name, array in seg.items() if name not in {"roi", "mask"}}
    roi_info = ROIInfo(seg["roi"], annotations=self.annotations, alternative=alternative)
    mask = seg["mask"] if "mask" in seg else None
    return roi_info, mask