code: def propose_layers(graphdef):
      concats = [
          node
          for node in graphdef.node
          if node.op in ["Concat", "ConcatV2", "Add"]
      ]
      branch_nodes = []
      for node in concats:
          branch_nodes += get_branch_nodes(graphdef, node)
  
      layer_proposals = [
          node
          for node in graphdef.node
          if node.op in ["Relu", "Concat", "ConcatV2", "Softmax", "Add"]
          and node.name not in branch_nodes
      ]
  
      return layer_proposals
  
imports: import lucid.optvis.render
label_desc: Use image node_id 3 for calling a global function with example usage: propose_layers(graphdef) and returns: layer_proposals