code: def forward(self, x: Tensor, edge_index: Tensor) -> Tensor:
      x = self.lin1(x).relu()
      x = self.conv1(x, edge_index).relu()
      x = self.lin2(x)
      return x
  
imports: from typing import Optional
  import pytest
  import torch
  from torch import Tensor, nn
  import torch_geometric.typing
  from torch_geometric.nn import Linear, SAGEConv, summary, to_hetero
  from torch_geometric.nn.models import GCN
  from torch_geometric.testing import withPackage
  from torch_geometric.typing import SparseTensor
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: x