Update pdf_qa.py

pdf_qa.py

@@ -90,5 +90,5 @@ async def main(message:str):
     chain = cl.user_session.get("chain")
     cb = cl.AsyncLangchainCallbackHandler()
     res = await chain.ainvoke(message, callbacks=[cb])
-    answer = res.content
+    answer = res
     await cl.Message(content=answer).send()