code: def get_conf(cls, builder, doctree=None):
          
  
          # set up the default conf
          result = {
              'theme': builder.config.slide_theme,
              'autoslides': builder.config.autoslides,
              'slide_classes': [],
          }
  
          # now look for a slideconf node in the doctree and update the conf
          if doctree:
              conf_node = cls.get(doctree)
              if conf_node:
                  result.update(conf_node.attributes)
  
          return result
docs: Return a dictionary of slide configuration for this doctree.