Update app.py

app.py

@@ -43,6 +43,7 @@ class model:
         if self.model_name != model_name:
             if self.model_path is not None:
                 os.remove(self.model_path)
+                del self.model
             self.model_name = model_name
             model_ckpt_path = hf_hub_download(repo_id=f"HuangLab/{model_name}", filename="model.ckpt")
             self.model_path = model_ckpt_path