code: def node_dtypes(self) -> dict[AttrKey, Dtype]:
      return {key: val.dtype for key, val in self.node_values.items()}
  
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 13 for calling the Graph obj's underlying member method code with example usage: obj.node_dtypes() and returns: unknown