Update app.py

app.py

@@ -279,8 +279,9 @@ def rag_answer(db: FAISS, llm: ChatNVIDIA, question: str, k: int = 4, max_contex
         f"### Pergunta\n{question}"
     )
 
-    msg = [("system", system_msg), ("user", user_prompt)]
-    llm_text = llm.invoke(msg).content
+    from langchain_core.messages import SystemMessage, HumanMessage
+    messages = [SystemMessage(content=system_msg), HumanMessage(content=user_prompt)]
+    llm_text = llm.invoke(messages).content
     return format_answer(question, docs, llm_text)
 
 # ----------------------------