else condition is absent. this is causing an issue while running in colab.

_folder can be None. when the value is None, should not proceed for function calling with None value.

gallery_history.py

@@ -28,7 +28,7 @@ if _folder is None:
         "locally and will be lost when the Space instance is restarted."
     )
     _folder = Path(__file__).parent / "history"
-if _folder.startswith("/data") and not os.path.exists("/data"):
+elif _folder.startswith("/data") and not os.path.exists("/data"):
     print(
         f"'HISTORY_FOLDER' environment variable is set to '{_folder}' which doesn't exist. User history will be saved "
         "locally and will be lost when the Space instance is restarted."