Fix aesthetic scorer

ddpo_pytorch/aesthetic_scorer.py

@@ -5,6 +5,7 @@ import torch
 import torch.nn as nn
 import numpy as np
 from transformers import CLIPModel, CLIPProcessor
+from PIL import Image
 
 ASSETS_PATH = resources.files("ddpo_pytorch.assets")
 
@@ -40,6 +41,8 @@ class AestheticScorer(torch.nn.Module):
 
     @torch.no_grad()
     def __call__(self, images):
+        assert isinstance(images, list)
+        assert isinstance(images[0], Image.Image)
         inputs = self.processor(images=images, return_tensors="pt")
         inputs = {k: v.cuda() for k, v in inputs.items()}
         embed = self.clip.get_image_features(**inputs)