code: def sentiment(self):
          
          if self._sentiment is None:
              results = self._xml.xpath('/root/document/sentences')
              self._sentiment = float(results[0].get("averageSentiment", 0)) if len(results) > 0 else None
          return self._sentiment
docs: Returns average sentiment of document. Must have sentiment enabled in XML output.
  
          :getter: returns average sentiment of the document
          :type: float