Update ai_assistant.py

ai_assistant.py

@@ -6,6 +6,7 @@ from langchain_community.vectorstores import FAISS
 from langchain.storage import LocalFileStore
 from langchain.chains import RetrievalQA
 from langchain_openai import ChatOpenAI
+from langchain_core.callbacks import StdOutCallbackHandler
 
 def create_index():
     # Load the data from CSV file