code: def parse_doc(doc):
      
      word_spans = []
      sentence_spans = []
      sentence_chunks = doc.split('\n\n')
      sentences = []
      for chunk in sentence_chunks:
          sent_texts, sent_labels = get_texts_and_labels(chunk.strip())
          sentences.append(list(zip(sent_texts, sent_labels)))
      return sentences
docs: Exract list of sentences containing (text, label) pairs.