code: def id_to_key(self) -> [NodeKey] | None:
      if self.key_to_id is None:
          return None
      if self._id_to_key is None:
          self._id_to_key = sorted(
              self.key_to_id, key=self.key_to_id.__getitem__
          )
      return self._id_to_key
  
imports: from __future__ import annotations
  import operator
  from copy import deepcopy
  from typing import TYPE_CHECKING
  import cupy
  import networkx
  import numpy
  import pylibcugraph
  import nx_cugraph
  from ..utils import index_dtype
label_desc: Use image node_id 14 for calling the Graph obj's underlying member method code with example usage: obj.id_to_key() and returns: self, None