code: def index_document(self, text, url):
          "Index the text of a document."
          ## For now, use first line for title
          title = text[:text.index('\n')].strip()
          docwords = words(text)
          docid = len(self.documents)
          self.documents.append(Document(title, url, len(docwords)))
          for word in docwords:
              if word not in self.stopwords:
                  self.index[word][docid] += f index_document(self, text, url):
          "Index the text of a document."
          ## For now, use first line for title
          title = text[:text.index('\n')].strip()
          docwords = words(text)
          docid = len(self.documents)
          self.documents.append(Document(title, url, len(docwords)))
          for word in docwords:
              if word not in self.stopwords:
                  self.index[word][docid] += 1
docs: Index the text of a document.