Update vtoonify_model.py

vtoonify_model.py

@@ -144,7 +144,7 @@ class Model():
     #@torch.inference_mode()
     def detect_and_align_image(self, frame_rgb: np.ndarray, top: int, bottom: int, left: int, right: int) -> tuple[np.ndarray, torch.Tensor, str]:
         if frame_rgb is None:
-        return np.zeros((256, 256, 3), np.uint8), None, 'Error: fail to load the image.'
+           return np.zeros((256, 256, 3), np.uint8), None, 'Error: fail to load the image.'
 
     # Convert RGB to BGR
         frame_bgr = cv2.cvtColor(frame_rgb, cv2.COLOR_RGB2BGR)