code: def forward(self, x, edge_index):
      x = self.conv1(x, edge_index).relu()
      return self.conv2(x, edge_index)
  
file_path: pytorch_geometric/test/explain/algorithm/test_explain_algorithm_utils.py
imports: import torch
  from torch_geometric.explain.algorithm.utils import clear_masks, set_hetero_masks
  from torch_geometric.nn import GCNConv, HeteroConv, SAGEConv, to_hetero
label_desc: Use image node_id 2 for calling the GraphSAGE obj's underlying member method code with example usage: obj.forward(x, edge_index) and returns: self