Update Gradio_UI.py

Gradio_UI.py

@@ -146,7 +146,10 @@ def stream_to_gradio(
             total_input_tokens += token_count
             # total_input_tokens += agent.model.last_input_token_count
             
-            total_output_tokens += agent.model.last_output_token_count
+            # total_output_tokens += agent.model.last_output_token_count
+            if agent.model.last_output_token_count is not None:
+                total_output_tokens += agent.model.last_output_token_count
+
             if isinstance(step_log, ActionStep):
                 step_log.input_token_count = agent.model.last_input_token_count
                 step_log.output_token_count = agent.model.last_output_token_count