code: def authkeywords(self):
          
          keywords = self._json['authkeywords']
          if keywords is None:
              return None
          else:
              try:
                  return [d['$'] for d in keywords['author-keyword']]
              except TypeError:  # Singleton keyword
                  return [keywords['author-keyword']['$']]
docs: List of author-provided keywords of the abstract.