code: def reverse_edge_type(etype: EdgeType) -> EdgeType:
      src, rel, dst = etype
      if src != dst:
          if rel.split("_", 1)[0] == "rev":
              # undirected edge with `rev_` prefix.
              rel = rel.split("_", 1)[1]
          else:
              rel = "rev_" + rel
  
      return dst, rel, src
  
file_path: pytorch_geometric/torch_geometric/distributed/utils.py
imports: from typing import Dict, List, Optional, Tuple, Union
  import numpy
  import torch
  from torch import Tensor
  from torch_geometric.data import HeteroData
  from torch_geometric.distributed import LocalFeatureStore, LocalGraphStore
  from torch_geometric.sampler import SamplerOutput
  from torch_geometric.typing import EdgeType, NodeType
label_desc: Use image node_id 4 for calling a global function with example usage: reverse_edge_type(etype) and returns: dst,  rel,  src