code: def run(self):
          
          self._env = self.state.document.settings.env
  
          nodes = []
  
          if 'toctree' in self.options:
              # Insert a hidden toctree
              toctree_node = self._build_toctree()
              nodes.append(toctree_node)
  
          # Placeholder node rendered in `process_task_topic_list`
          list_node = task_topic_list()
          list_node['types'] = self.types
          list_node['root_namespace'] = self.options['root']
          nodes.append(list_node)
  
          return nodes
docs: Main entrypoint method.
  
          Returns
          -------
          new_nodes : `list`
              Nodes to add to the doctree.