update, because last one not working

app.py

@@ -3,10 +3,7 @@ import os
 from langchain_community.vectorstores import Chroma
 from langchain_community.embeddings import HuggingFaceBgeEmbeddings
 from langchain_community.llms import Together
-from langchain import hub
-from operator import itemgetter
-from langchain.chains import LLMChain
-from langchain.chains import ConversationalRetrievalChain
+from langchain.chains import ConversationalRetrievalChain, LLMChain
 from langchain.prompts import ChatPromptTemplate, MessagesPlaceholder, PromptTemplate
 from langchain.memory import ConversationBufferMemory
 from langchain_community.chat_message_histories import StreamlitChatMessageHistory
@@ -98,12 +95,15 @@ def app():
     Question: {question}"""
     ANSWER_PROMPT = ChatPromptTemplate.from_template(answer_template)
 
+    question_generator_chain = LLMChain(llm=llmc, prompt=CONDENSE_QUESTION_PROMPT)
+    qa_chain = LLMChain(llm=llm, prompt=ANSWER_PROMPT)
+
     conversational_qa_chain = ConversationalRetrievalChain(
         retriever=retriever,
         memory=memory,
         combine_docs_chain=_combine_documents,
-        condense_question_chain=LLMChain(llm=llmc, prompt=CONDENSE_QUESTION_PROMPT),
-        qa_chain=LLMChain(llm=llm, prompt=ANSWER_PROMPT)
+        question_generator=question_generator_chain,
+        qa_chain=qa_chain
     )
 
     st.header("Ask Away!")