Update app.py

app.py

@@ -22,15 +22,16 @@ DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
 # ----- THIS IS WERE YOU CAN BUILD WHAT YOU WANT ------
 class BasicAgent:
     def __init__(self):
-        print("Initializing LangChain Agent...")
+        print("Initializing LangGraph Agent...")
         self.agent = create_langchain_agent()
 
     def __call__(self, question: str) -> str:
         try:
-            result = self.agent.invoke({"input": question})
-            if isinstance(result, dict) and "output" in result:
-                return result["output"]
-            return result
+            # LangGraph uses a modern message-based format
+            result = self.agent.invoke({"messages": [("user", question)]})
+            
+            # The final answer is the content of the very last message in the chain
+            return result["messages"][-1].content
         except Exception as e:
             return f"Agent error: {e}"