code: def parse(self, limit=None):
          
  
          if self.test_only:
              self.test_mode = True
  
          self._get_titles(limit)
          self._get_equivids(limit)
  
          self.create_books()
          self.process_nbk_html(limit)
  
          # no test subset for now; test == full graph
          self.testgraph = self.graph
          return
docs: :return: None