原代码：

def extract_features(img_dir, model):     try:         cache = Cache('./tmp')         feats = []         names = []         img_list = get_imgs(img_dir)         total = len(img_list)         cache['total'] = total         for i, img_path in enumerate(img_list):             try:                 norm_feat = model.resnet50_extract_feat(img_path)                 feats.append(norm_feat)                 names.append(img_path.encode())                 cache['current'] = i + 1                 print(f"Extracting feature from image No. {i + 1} , {total} images in total")             except Exception as e:                 LOGGER.error(f"Error with extracting feature from image {e}")                 continue         return feats, names     except Exception as e:         LOGGER.error(f"Error with extracting feature from image {e}")         sys.exit(1) 

大概位置是下面这里：

def extract_features(img_dir, model):     try:         cache = Cache('./tmp')         feats = []         names = []         img_list = get_imgs(img_dir)         total = len(img_list)         cache['total'] = total         #check if img_dir is a image or image_path         #if it is image, create embedding and return, else, traverse the directory         for i, img_path in enumerate(img_list):             #extract feature         return feats, names     except Exception as e:         LOGGER.error(f"Error with extracting feature from image {e}")         sys.exit(1) 

请问一下应该如何写啊？ 判断传入的是图片文件名还是目录