Shows `ys` (target images) on a figure of `figsize`.

def show_xys(self, xs, ys, imgsize:int=4, figsize:Optional[Tuple[int,int]]=None, **kwargs):
        "Shows `ys` (target images) on a figure of `figsize`."
        super().show_xys(ys, xs, imgsize=imgsize, figsize=figsize, **kwargs)