adding dependencies

Gradio_UI.py

@@ -142,15 +142,15 @@ def stream_to_gradio(
     for step_log in agent.run(task, stream=True, reset=reset_agent_memory, additional_args=additional_args):
         # Track tokens if model provides them
         if hasattr(agent.model, "last_input_token_count"):
-            total_input_tokens += agent.model.last_input_token_count
-            total_output_tokens += agent.model.last_output_token_count
+            last_input_token_count = agent.model.last_input_token_count or 0
+            last_output_token_count = agent.model.last_output_token_count or 0
+            total_input_tokens += last_input_token_count
+            total_output_tokens += 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
-
-        for message in pull_messages_from_step(
-            step_log,
-        ):
+                step_log.input_token_count = last_input_token_count
+                step_log.output_token_count = last_output_token_count
+    
+        for message in pull_messages_from_step(step_log):
             yield message
 
     final_answer = step_log  # Last log is the run's final_answer