code: import os
  from llama_index import GPTVectorStoreIndex, SimpleDirectoryReader
  from IPython.display import Markdown, display
  from llama_index import StorageContext, load_index_from_storage
  
  # Set the OPENAI_API_KEY environment variable using the value from st.secrets['OPENAI_API_KEY']
  os.environ['OPENAI_API_KEY'] = st.secrets['OPENAI_API_KEY']
  
  # Load documents from the 'data' directory
  documents = SimpleDirectoryReader('data').load_data()
  
  # Create an index from the loaded documents
  index = GPTVectorStoreIndex.from_documents(documents)
  
  # Save the index to disk
  index.storage_context.persist(persist_dir="./storage")
  
  # Load the index from disk for testing
  # loaded_index = load_index_from_storage(StorageContext.from_defaults(persist_dir="./storage"))
  
  # Create a query engine from the loaded index
  # query_engine = loaded_index.as_query_engine()
  
  # Perform a query using the query engine
  # response = query_engine.query("What is Citizens Round?")
  # print(response)
  
apis: llama_index.GPTVectorStoreIndex.from_documents llama_index.SimpleDirectoryReader
extract_api: [((495, 540), 'llama_index.GPTVectorStoreIndex.from_documents', 'GPTVectorStoreIndex.from_documents', (['documents'], {}), '(documents)\n', (529, 540), False, 'from llama_index import GPTVectorStoreIndex, SimpleDirectoryReader\n'), ((400, 429), 'llama_index.SimpleDirectoryReader', 'SimpleDirectoryReader', (['"""data"""'], {}), "('data')\n", (421, 429), False, 'from llama_index import GPTVectorStoreIndex, SimpleDirectoryReader\n')]