updated langchain predict

app.py

@@ -105,7 +105,7 @@ class CustomChatModelAdvanced(BaseChatModel):
         """
         # Replace this with actual logic to generate a response from a list
         # of messages.
-        last_message = messages[-1]
+        last_message = messages[-1].content
         tokens = predict(last_message)
         message = AIMessage(
             content=tokens,