code: def forward(self, x, edge_index, *args, **kwargs):
      # x=[x_stem,[x_sides]]
      # use dot-product attn
      x1, x2, x3 = x[0], x[1][0], x[1][1]  # q,k,v
      skip_connect, norm = self.skip_connect, self.norm
      if not skip_connect and not norm:
          return self.propagate(edge_index, x1=x1, x2=x2, x3=x3)
  
      x = self.propagate(edge_index, x1=x1, x2=x2, x3=x3)
      if not norm:
          return x
  
      if not skip_connect:
          return self.ln_attn(x)
      return self.ln_attn(x + x1)
  
imports: from torch_geometric.nn import MessagePassing
  from torch_geometric.utils import softmax
  import torch
  import torch.nn
  import torch.nn.functional
  from torch_geometric.nn import GCNConv, SAGEConv, GATConv, ARMAConv, ChebConv, GatedGraphConv, SGConv
  from typing import Union, Tuple, Optional
  from torch_geometric.typing import OptPairTensor, Adj, Size, NoneType, OptTensor
  import torch
  from torch import Tensor
  import torch.nn.functional
  from torch.nn import Parameter, Linear
  from torch_sparse import SparseTensor, set_diag
  from torch_geometric.nn.conv import MessagePassing
  from torch_geometric.utils import remove_self_loops, add_self_loops, softmax
  from torch_geometric.nn.inits import glorot, zeros
  import torch
  import torch.nn
  import torch.nn.functional
  import torch.nn.functional
  from torch.nn import Parameter
  from torch_geometric.nn.inits import glorot, zeros
  from torch_geometric.utils import softmax
  from torch_scatter import scatter_add
  import numpy
  from ..graph_nas_macro import GeoLayer
label_desc: Use image node_id 3 for calling the AggAttn obj's underlying member method code with example usage: obj.forward(x, edge_index) and returns: self, self, x, self