def METHOD_NAME(out_file):
    """Automatically rename out_file when duplicated file exists.
    This case occurs when there is multiple instances on one image.
    """
    if out_file and osp.exists(out_file):
        img_name, postfix = osp.basename(out_file).rsplit('.', 1)
        exist_files = tuple(
            filter(lambda f: f.startswith(img_name),
                   os.listdir(osp.dirname(out_file))))
        if len(exist_files) > 0:
            img_path = f'{img_name}({len(exist_files)}).{postfix}'
            out_file = osp.join(osp.dirname(out_file), img_path)
    return out_file