Update app.py

app.py

@@ -1,5 +1,6 @@
 from dotenv import load_dotenv
 import gradio as gr
+import os
 from llama_index.core import StorageContext, load_index_from_storage, VectorStoreIndex, SimpleDirectoryReader, ChatPromptTemplate, Settings
 from llama_index.llms.huggingface import HuggingFaceInferenceAPI
 from llama_index.embeddings.huggingface import HuggingFaceEmbedding