Update Gradio_UI.py

Gradio_UI.py

@@ -130,7 +130,7 @@ def stream_to_gradio(
     additional_args: Optional[dict] = None,
 ):
     """Runs an agent with the given task and streams the messages from the agent as gradio ChatMessages."""
-    if not is_package_available("gradio"):
+    if not _is_package_available("gradio"):
         raise ModuleNotFoundError(
             "Please install 'gradio' extra to use the GradioUI: `pip install 'smolagents[gradio]'`"
         )