Update app.py

app.py

@@ -8,8 +8,9 @@ import numpy as np
 from langchain_community.vectorstores import Chroma
 from langchain_community.document_loaders import UnstructuredPDFLoader, PyPDFLoader
 from langchain.text_splitter import CharacterTextSplitter
-from langchain.chains import RetrievalQAWithSourcesChain
-from langchain.chains import load_qa_with_sources_from_chain_type
+# from langchain.chains import RetrievalQAWithSourcesChain
+# from langchain.chains import load_qa_with_sources_from_chain_type
+from langchain.chains import ConversationalRetrievalChain
 from langchain.schema import Document
 from langchain.memory import ConversationBufferMemory
 from langchain.callbacks.manager import CallbackManager
@@ -76,14 +77,15 @@ def initialize_LLM(llm_option, llm_temperature, max_tokens, top_k, vector_db, pr
     if llm_name != default_llm:
         print(f"Using default LLM {default_llm} for {language}")
         llm_name = default_llm
-    
-    qa_chain = load_qa_with_sources_from_chain_type(
+
+    qa_chain = ConversationalRetrievalChain.from_llm(
         llm=llm_name,
-        chain_type="stuff",
         retriever=vector_db.as_retriever(),
+        chain_type="stuff",
+        memory=memory,
+        return_source_documents=True,
         temperature=llm_temperature,
-        top_k_per_token=top_k,
-        max_tokens=max_tokens,
+        verbose=False,
     )
     progress.update(1.0)
     logger.info("LLM chain initialized successfully.")