code: from llama_index.core.node_parser import SentenceWindowNodeParser
  from llama_index.readers.file import FlatReader
  from pathlib import Path
  
  reader = FlatReader()
  document = reader.load_data(Path("files/sample_document1.txt"))
  
  parser = SentenceWindowNodeParser.from_defaults(
      window_size=2,  
      window_metadata_key="text_window",  
      original_text_metadata_key="original_sentence" 
  )
  nodes = parser.get_nodes_from_documents(document)
  
  for node in nodes:
      print(f"Metadata {node.metadata} \nText: {node.text}\n")
apis: llama_index.readers.file.FlatReader llama_index.core.node_parser.SentenceWindowNodeParser.from_defaults
extract_api: [((149, 161), 'llama_index.readers.file.FlatReader', 'FlatReader', ([], {}), '()\n', (159, 161), False, 'from llama_index.readers.file import FlatReader\n'), ((236, 377), 'llama_index.core.node_parser.SentenceWindowNodeParser.from_defaults', 'SentenceWindowNodeParser.from_defaults', ([], {'window_size': '(2)', 'window_metadata_key': '"""text_window"""', 'original_text_metadata_key': '"""original_sentence"""'}), "(window_size=2, window_metadata_key=\n    'text_window', original_text_metadata_key='original_sentence')\n", (274, 377), False, 'from llama_index.core.node_parser import SentenceWindowNodeParser\n'), ((190, 224), 'pathlib.Path', 'Path', (['"""files/sample_document1.txt"""'], {}), "('files/sample_document1.txt')\n", (194, 224), False, 'from pathlib import Path\n')]