fix basic agent

app.py

@@ -14,26 +14,19 @@ DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
 # --- Basic Agent Definition ---
 # ----- THIS IS WERE YOU CAN BUILD WHAT YOU WANT ------
 class BasicAgent:
+    """A langgraph agent."""
     def __init__(self):
         print("BasicAgent initialized.")
         self.graph = build_graph()
 
     def __call__(self, question: str) -> str:
         print(f"Agent received question (first 50 chars): {question[:50]}...")
+        # Wrap the question in a HumanMessage from langchain_core
         messages = [HumanMessage(content=question)]
-        result = self.graph.invoke({"messages": messages})
-        # Extract the final answer message from the state
-        # The final message should be the content of the last AIMessage
-        submitted_answer = "Could not get answer from agent output." # Default if extraction fails
-        if result and "messages" in result:
-            for msg in reversed(result["messages"]): # Look for the last AI message
-                # Check if the message is an AIMessage and has content
-                if isinstance(msg, AIMessage) and hasattr(msg, 'content') and msg.content:
-                    # Convert content to string to ensure type consistency with return hint
-                    submitted_answer = str(msg.content)
-                    break # Found the last AI message content
-
-        return submitted_answer
+        messages = self.graph.invoke({"messages": messages})
+        answer = messages['messages'][-1].content
+        return answer[14:]
+
 
 def run_and_submit_all( profile: gr.OAuthProfile | None):
     """