Update app.py

app.py

@@ -39,7 +39,7 @@ from llama_index.vector_stores import DeepLakeVectorStore
 # Create an index over the documnts
 vector_store = DeepLakeVectorStore(dataset_path=dataset_path,reset=True
                                     )
-
+service_context = ServiceContext.from_defaults()
 storage_context = StorageContext.from_defaults(vector_store=vector_store)
                                     
 index = VectorStoreIndex.from_documents([], storage_context=storage_context)