Changed to ChatOpenAI

app.py

@@ -3,7 +3,7 @@ import urllib.request
 from langchain.chains import RetrievalQA
 from langchain_community.document_loaders import UnstructuredHTMLLoader
 from langchain_openai import OpenAIEmbeddings
-from langchain_openai.llms import OpenAI
+from langchain_openai import ChatOpenAI
 from langchain.text_splitter import CharacterTextSplitter
 from langchain_community.vectorstores import Chroma
 
@@ -30,7 +30,7 @@ db = Chroma.from_documents(texts, embeddings)
 retriever = db.as_retriever(search_type="similarity", search_kwargs={"k": 2})
 # create a chain to answer questions
 qa = RetrievalQA.from_chain_type(
-    llm=OpenAI(model="gpt-3.5-turbo-0125"),
+    llm=ChatOpenAI(),
     chain_type="stuff",
     retriever=retriever,
     return_source_documents=True,