code: def forward(self, x, edge_index):
      x = self.conv1(x, edge_index).relu()
      x = self.conv2(x, edge_index)
      return x
  
file_path: pytorch_geometric/examples/explain/captum_explainer_hetero_link.py
imports: import os.path
  import torch
  import torch.nn.functional
  from torch.nn import Linear
  import torch_geometric.transforms
  from torch_geometric.datasets import MovieLens
  from torch_geometric.explain import CaptumExplainer, Explainer
  from torch_geometric.nn import SAGEConv, to_hetero
label_desc: Use image node_id 2 for calling the GNNEncoder obj's underlying member method code with example usage: obj.forward(x, edge_index) and returns: x