Update app.py

app.py

@@ -13,7 +13,7 @@ MODEL_URL = "https://huggingface.co/boltz-community/boltz-1/resolve/main/boltz1.
 
 cache = "~/.boltz"
 ccd = f"{cache}/ccd.pkl"
-if not ccd.exists():
+if not os.path.exists(ccd):
     print(
         f"Downloading the CCD dictionary to {ccd}. You may "
     )
@@ -21,7 +21,7 @@ if not ccd.exists():
 
 # Download model
 model =f"{cache}/boltz1.ckpt"
-if not model.exists():
+if not os.path.exists(model):
     print(
         f"Downloading the model weights to {model}"
     )