update runnable config

app.py

@@ -4,7 +4,7 @@ from datasets import load_dataset
 from langchain.embeddings import CacheBackedEmbeddings
 from langchain.storage import LocalFileStore
 from langchain.text_splitter import RecursiveCharacterTextSplitter
-from langchain_core.runnables.base import RunnableSequence
+from langchain_core.runnables import RunnableConfig
 from langchain_core.runnables.passthrough import RunnablePassthrough
 from langchain_core.output_parsers import StrOutputParser
 from langchain_core.prompts import ChatPromptTemplate
@@ -67,10 +67,9 @@ async def on_chat_start():
 async def main(message):
     print("On Message Start")
     chain = cl.user_session.get("chain")
-    cb = cl.AsyncLangchainCallbackHandler()
     user_input = cl.Message(content="")
     await user_input.send()
 
-    async for stream in chain.astream(user_input.content, cb):
+    async for stream in chain.astream(user_input.content, config=RunnableConfig(callbacks=[cl.LangchainCallbackHandler()])):
         print("Stream is: " + stream)
         await user_input.stream_token(stream)