code: def edge_attention(self, edge):
      a = F.leaky_relu(
          edge.src["a1"] + edge.dst["a2"], self.negative_slope
      )
      return {"a": a}
  
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 GATSPMVConv obj's underlying member method code with example usage: obj.edge_attention(edge) and returns: dict