Update app.py

app.py

@@ -10,8 +10,10 @@ import glob
 from langchain.embeddings.openai import OpenAIEmbeddings
 from langchain.vectorstores import Chroma
 from langchain.text_splitter import TokenTextSplitter
-from langchain.llms import OpenAI
-from langchain.chains import ChatVectorDBChain
+#from langchain.llms import OpenAI
+from langchain.chat_models import ChatOpenAI
+#from langchain.chains import ChatVectorDBChain
+from langchain.chains import RetrievalQA
 from langchain.document_loaders import PyPDFLoader
 
 # Use Chroma in Colab to create vector embeddings, I then saved them to HuggingFace so now I have to set it use them here.
@@ -100,7 +102,7 @@ def submit_message(prompt, prompt_template, temperature, max_tokens, context_len
 
 # completion = openai.ChatCompletion.create(model="gpt-3.5-turbo", messages=system_prompt + history[-context_length*2:] + [prompt_msg], temperature=temperature, max_tokens=max_tokens)
 
-        completion = ChatVectorDBChain.from_llm(OpenAI(temperature=temperature, max_tokens=max_tokens, model_name="gpt-3.5-turbo"), vectordb, return_source_documents=True)
+        completion = RetrievalQA.from_chain_type(llm=ChatOpenAI(temperature=temperature, max_tokens=max_tokens, model_name="gpt-3.5-turbo"), chain_type="stuff", retriever=vectordb.as_retriever() , return_source_documents=True)
         result = completion({"question": system_prompt + [prompt_msg], "chat_history": history[-context_length*2:]})
         # from https://blog.devgenius.io/chat-with-document-s-using-openai-chatgpt-api-and-text-embedding-6a0ce3dc8bc8