update vis script

vis_hit_sample.py

@@ -90,6 +90,7 @@ if __name__ == '__main__':
         idx = random.randint(0, N_dataset)
     else:
         idx = args.idx
+        assert idx < N_dataset, f"{idx} in {args.gender}:{args.split} is out of range for dataset of length {N_dataset}."
 
     # get sample
     hit_sample = hit_dataset[idx]