code: def powernode_data(self, name:str) -> Powernode:
          
          self.assert_powernode(name)
          contained_nodes = frozenset(self.nodes_in(name))
          return Powernode(
              size=len(contained_nodes),
              contained=frozenset(self.all_in(name)),
              contained_pnodes=frozenset(self.powernodes_in(name)),
              contained_nodes=contained_nodes,
          )
docs: Return a Powernode object describing the given powernode