code: def _add_bias(self, edges):
      bias_src = self.bias[edges.src[dgl.NID]]
      bias_dst = self.bias[edges.dst[dgl.NID]]
      return {"s": edges.data["s"] + bias_src + bias_dst}
  
imports: import dgl
  import dgl.function
  import dgl.nn.pytorch
  import torch
  import torch.nn
  import torch.nn.functional
label_desc: Use image node_id 2 for calling the ItemToItemScorer obj's underlying member method code with example usage: obj._add_bias(edges) and returns: dict