Update app.py

app.py

@@ -21,7 +21,8 @@ from langchain_openai import OpenAI
 from langchain.llms import OpenAI
 from transformers import AutoTokenizer,pipeline 
 from langchain.chat_models import ChatOpenAI
-
+from langchain.vectorstores import Chroma
+from langchain.embeddings.sentence_transformer import SentenceTransformerEmbeddings
 
 #HF_TOKEN = os.getenv('HF_TOKEN')
 #OPENAI_API_KEY = os.getenv('OPENAI_API_KEY')