fix: use default values

app.py

@@ -5,15 +5,19 @@ import os
 hf_api = HfApi()
 CURRENT_MODEL_PATH = "./current_model"
 
+HF_TOKEN = os.environ.get("HF_TOKEN", None)
+REPO = os.getenv("REPO")
+REVISION = os.getenv("REVISION")
+
 def func(hf_token, repo, revision, target_repo):
     print('download the desired model locally ...')
     hf_api.snapshot_download(
-        repo_id=repo,
-        revision=revision,
-        token=hf_token,
+        repo_id=repo if len(repo)>0 else REPO,
+        revision=revision if len(revision)>0 else REVISION,
+        token=hf_token if len(hf_token)>0 else HF_TOKEN,
         local_dir=CURRENT_MODEL_PATH,
     )
-    os.listdir(CURRENT_MODEL_PATH)
+    print(os.listdir(CURRENT_MODEL_PATH))
     
     return f"Using {hf_token}, the content of {repo}/{revision} has been copied to {target_repo}!"