class_docstr: Bundler, which will be the node_apply function in DGL paradigm
code: def concat(self, h, aggre_result):
      bundle = torch.cat((h, aggre_result), 1)
      bundle = self.linear(bundle)
      return bundle
  
file_path: dgl/examples/pytorch/diffpool/model/dgl_layers/bundler.py
imports: import torch
  import torch.nn
  import torch.nn.functional
label_desc: Use image node_id 2 for calling the Bundler obj's underlying member method code with example usage: obj.concat(h, aggre_result) and returns: bundle