code: from llama_index.core import SimpleDirectoryReader
  from llama_index.core.node_parser import SentenceSplitter
  from llama_index.core.extractors import KeywordExtractor
  
  reader = SimpleDirectoryReader('files')
  documents = reader.load_data()
  parser = SentenceSplitter(include_prev_next_rel=True)
  nodes = parser.get_nodes_from_documents(documents)
  
  key_extractor = KeywordExtractor(keywords=3)
  metadata_list = key_extractor.extract(nodes)
  
  print(metadata_list)
  
apis: llama_index.core.node_parser.SentenceSplitter llama_index.core.SimpleDirectoryReader llama_index.core.extractors.KeywordExtractor
extract_api: [((176, 206), 'llama_index.core.SimpleDirectoryReader', 'SimpleDirectoryReader', (['"""files"""'], {}), "('files')\n", (197, 206), False, 'from llama_index.core import SimpleDirectoryReader\n'), ((247, 291), 'llama_index.core.node_parser.SentenceSplitter', 'SentenceSplitter', ([], {'include_prev_next_rel': '(True)'}), '(include_prev_next_rel=True)\n', (263, 291), False, 'from llama_index.core.node_parser import SentenceSplitter\n'), ((360, 388), 'llama_index.core.extractors.KeywordExtractor', 'KeywordExtractor', ([], {'keywords': '(3)'}), '(keywords=3)\n', (376, 388), False, 'from llama_index.core.extractors import KeywordExtractor\n')]