code: def forward(self, x, edge_index, add_self=False):
      edge_index, _ = pyg_utils.remove_self_loops(edge_index)
      emb = self.propagate(edge_index, size=(x.size(0), x.size(0)), x=x)
      if add_self:
          emb = emb + x
      return emb
  
file_path: deepsnap/examples/graph_classification/skip_models.py
imports: import torch
  import torch.nn
  import torch.nn.functional
  import torch_geometric.nn
  import torch_geometric.utils
label_desc: Use image node_id 3 for calling the SimpleConv obj's underlying member method code with example usage: obj.forward(x, edge_index, add_) and returns: emb