Update app.py

app.py

@@ -123,8 +123,9 @@ def load_chain():
     '''Load langchain Conversational Retrieval Chain'''
     
     vectorstore = load_vectorstore(embeddings)
-    llm = ChatOpenAI(temperature=0)
-    streaming_llm = ChatOpenAI(streaming=True, 
+    llm = ChatOpenAI(temperature=0, model_name='gpt-4')
+    streaming_llm = ChatOpenAI(model_name='gpt-4',
+                               streaming=True, 
                                callback_manager=CallbackManager([StreamingStdOutCallbackHandler()]), 
                                verbose=True, 
                                temperature=0)