Update app.py

app.py

@@ -2,6 +2,8 @@ from langchain.prompts.prompt import PromptTemplate
 from langchain.llms import OpenAI
 from langchain.chains import ChatVectorDBChain
 from langchain.embeddings import HuggingFaceEmbeddings, HuggingFaceInstructEmbeddings
+from langchain.callbacks.base import CallbackManager
+from langchain.callbacks.streaming_stdout import StreamingStdOutCallbackHandler
 from langchain.vectorstores import FAISS
 import os
 from typing import Optional, Tuple
@@ -62,7 +64,7 @@ QA_PROMPT = PromptTemplate(template=template, input_variables=["question", "cont
 
 
 def get_chain(vectorstore):
-    llm = OpenAI(temperature=0)
+    llm = OpenAI(streaming=True, callback_manager=CallbackManager([StreamingStdOutCallbackHandler()]), verbose=True, temperature=0)
     qa_chain = ChatVectorDBChain.from_llm(
         llm,
         vectorstore,