code: def key2str(key: Union[NodeType, EdgeType]) -> str:
      key = "__".join(key) if isinstance(key, tuple) else key
      return key.replace(" ", "_").replace("-", "_").replace(":", "_")
  
imports: import copy
  import warnings
  from typing import Any, Dict, List, Optional, Union
  import torch
  from torch import Tensor
  from torch.nn import Module, Parameter
  from torch_geometric.nn.conv import MessagePassing
  from torch_geometric.nn.dense import Linear
  from torch_geometric.nn.fx import Transformer
  from torch_geometric.typing import EdgeType, Metadata, NodeType, SparseTensor
  from torch_geometric.utils.hetero import get_unused_node_types
label_desc: Use image node_id 8 for calling a global function with example usage: key2str(key) and returns: key