Update app.py

app.py

@@ -5,7 +5,7 @@ from langchain.embeddings import CohereEmbeddings
 from langchain.vectorstores.faiss import FAISS
 from langchain.text_splitter import RecursiveCharacterTextSplitter
 from langchain.llms.fireworks import Fireworks 
-from langchain import VectorDBQA
+from langchain.chains import VectorDBQA
 
 FIREWORKS_API_KEY = os.getenv("FIREWORKS_API_KEY")