Update app.py

app.py

@@ -1,14 +1,19 @@
 import gradio as gr
 import os
-from llama_index.core import SimpleDirectoryReader, VectorStoreIndex, ServiceContext
+from llama_index.core import SimpleDirectoryReader, VectorStoreIndex, Settings
 from llama_index.llms.openai import OpenAI
 
-# Set your OpenAI API key
+# Set OpenAI API key from environment
 os.environ["OPENAI_API_KEY"] = os.getenv("OPENAI_API_KEY")
 
-# Load documents and create index
+# Configure the default LLM
+Settings.llm = OpenAI()
+
+# Load documents and build index
 documents = SimpleDirectoryReader("documents").load_data()
-index = VectorStoreIndex.from_documents(documents, service_context=ServiceContext.from_defaults(llm=OpenAI()))
+index = VectorStoreIndex.from_documents(documents)
+
+# Create query engine
 query_engine = index.as_query_engine()
 
 def chatbot_response(message):