code: def forward(self, batch):
      bond_embedding = 0
      for i in range(batch.edge_feature.shape[1]):
          bond_embedding += self.bond_embedding_list[i](
              batch.edge_attr[:, i]
          )
  
      batch.edge_attr = bond_embedding
      return batch
  
file_path: pytorch_geometric/graphgym/custom_graphgym/encoder/example.py
imports: import torch
  from ogb.utils.features import get_bond_feature_dims
  from torch_geometric.graphgym.register import register_edge_encoder, register_node_encoder
label_desc: Use image node_id 2 for calling the ExampleEdgeEncoder obj's underlying member method code with example usage: obj.forward(batch) and returns: batch