code: def gat_reduce(self, node):
      alpha = torch.softmax(node.mailbox["a"], dim=1)
      alpha = F.dropout(alpha, p=self.dropout, training=self.training)
      x = (node.mailbox["m"] * alpha.unsqueeze(-1)).sum(dim=1)
      return {"x": x}
  
imports: import dgl.function
  import torch
  import torch.nn.functional
  from dgl.nn.pytorch import EdgeSoftmax
  from torch.nn import Parameter
  from torch_geometric.nn.inits import glorot, zeros
label_desc: Use image node_id 4 for calling the GATConv obj's underlying member method code with example usage: obj.gat_reduce(node) and returns: dict