fix arguement error

app.py

@@ -213,28 +213,27 @@ async def main(message: cl.Message):
     try:
         lcel_rag_chain = cl.user_session.get("lcel_rag_chain")
 
-        # Create a message to stream to
-        msg = cl.Message(content="")
-        await msg.send()
-
         # Get the response as a single string
         response = await cl.make_async(lcel_rag_chain.invoke)(
             {"query": message.content},
             config=RunnableConfig(callbacks=[cl.LangchainCallbackHandler()]),
         )
         
-        # Update the message with the complete response
-        await msg.update(response)
+        # Send the response message
+        await cl.Message(
+            content=response,
+            author="Paul Graham Essay Bot"
+        ).send()
 
     except Exception as e:
         error_message = str(e)
         if "Connection reset by peer" in error_message or "Connection aborted" in error_message:
             await cl.Message(
                 content="I apologize, but I'm having trouble connecting to the language model right now. Please try again in a few moments. If the problem persists, the service might be temporarily unavailable.",
-                author="System"
+                author="Paul Graham Essay Bot"
             ).send()
         else:
             await cl.Message(
                 content=f"An error occurred: {error_message}. Please try again.",
-                author="System"
+                author="Paul Graham Essay Bot"
             ).send()