fix error: Invalid type for messages[0]

chatbot_simulator.py

@@ -146,7 +146,7 @@ Example Output Format:
                 'task_completed': 'False',
             }}
             """
-            updated_state = self._get_openai_response([{'role': 'system', 'content': transform_prompt}])
+            updated_state = self._get_openai_response([{"role": "system", "content": transform_prompt}])
             updated_state = json_repair.loads(updated_state)
 
         try: