Update app.py

app.py

@@ -41,7 +41,7 @@ def duplicate(source_repo, dst_repo, token, repo_type):
                 if ".git" not in root:
                     # remove hub/namespace/reponame
                     directory_path_in_repo = "/".join(root.split("/")[3:]) 
-                    path_in_repo = os.join(directory_path_in_repo, f)
+                    path_in_repo = os.path.join(directory_path_in_repo, f)
                     local_file_path = os.path.join(local_dir, path_in_repo)
                     print("From: ", local_file_path, " to: ", path_in_repo)
                     upload_file(path_or_fileobj=local_file_path, path_in_repo=path_in_repo, repo_id=dst_repo, token=token, repo_type=repo_type)