remove multiquery_retriever

app.py

@@ -12,7 +12,6 @@ from langchain.chains import ConversationalRetrievalChain
 from langchain_community.vectorstores import Qdrant
 from langchain.memory import ConversationBufferMemory
 from langchain_huggingface import HuggingFaceEmbeddings
-from langchain.retrievers.multi_query import MultiQueryRetriever
 
 import chainlit as cl
 
@@ -80,11 +79,6 @@ llm = ChatOpenAI(
     streaming=True,
 )
 
-retriever_llm = ChatOpenAI(model="gpt-4o-mini", temperature=0)
-multiquery_retriever = MultiQueryRetriever.from_llm(
-    retriever=retriever, llm=retriever_llm
-)
-
 
 @cl.on_chat_start
 async def start_chat():
@@ -94,7 +88,7 @@ async def start_chat():
 
     qa = ConversationalRetrievalChain.from_llm(
         llm,
-        retriever=multiquery_retriever,
+        retriever=retriever,
         memory=memory,
         combine_docs_chain_kwargs={"prompt": PROMPT},
         return_source_documents=True,