code: def forward(self, x: Tensor, edge_index: Tensor) -> Tensor:
      x_j = x[edge_index[0]]
      out = scatter(
          x_j, edge_index[1], dim_size=x.size(0), reduce="mean"
      )
      return self.lin_src(out) + self.lin_dst(x)
  
file_path: pytorch_geometric/test/nn/test_compile_conv.py
imports: import pytest
  import torch
  from torch import Tensor
  from torch_geometric.nn import GCNConv, SAGEConv
  from torch_geometric.profile import benchmark
  from torch_geometric.testing import onlyFullTest, onlyLinux, withCUDA, withPackage
  from torch_geometric.utils import scatter
label_desc: Use image node_id 2 for calling the MySAGEConv obj's underlying member method code with example usage: obj.forward(x, edge_index) and returns: unknown