class_docstr: This class implements the :class:`torch_geometric.data.GraphStore`
  interface to act as a local graph store for distributed training.
code: def key(attr: EdgeAttr) -> Tuple:
      return (attr.edge_type, attr.layout.value)
  
imports: import json
  import os.path
  from typing import Any, Dict, List, Optional, Tuple, Union
  import torch
  from torch import Tensor
  from torch_geometric.data import EdgeAttr, GraphStore
  from torch_geometric.typing import EdgeTensorType, EdgeType, NodeType
  from torch_geometric.utils import sort_edge_index
label_desc: Use image node_id 2 for calling the LocalGraphStore obj's underlying member method code with example usage: obj.key(attr) and returns: attr,  attr