code: def validate(self):
      unused_node_types = get_unused_node_types(*self.metadata)
      if len(unused_node_types) > 0:
          warnings.warn(
              f"There exist node types ({unused_node_types}) whose "
              f"representations do not get updated during message passing "
              f"as they do not occur as destination type in any edge type. "
              f"This may lead to unexpected behavior."
          )
  
      names = self.metadata[0] + [rel for _, rel, _ in self.metadata[1]]
      for name in names:
          if not name.isidentifier():
              warnings.warn(
                  f"The type '{name}' contains invalid characters which "
                  f"may lead to unexpected behavior. To avoid any issues, "
                  f"ensure that your types only contain letters, numbers "
                  f"and underscores."
              )
  
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 2 for calling the ToHeteroWithBasesTransformer obj's underlying member method code with example usage: obj.validate() without return types