Return `ImageSegment` object create from run-length encoded string in `mask_lre` with size in `shape`.

def open_mask_rle(mask_rle:str, shape:Tuple[int, int])->ImageSegment:
    "Return `ImageSegment` object create from run-length encoded string in `mask_lre` with size in `shape`."
    x = FloatTensor(rle_decode(str(mask_rle), shape).astype(np.uint8))
    x = x.view(shape[1], shape[0], -1)
    return ImageSegment(x.permute(2,0,1))