code: def get_branch_nodes(graphdef, concat_node):
      branch_head_names = concat_node.input[:]
      branch_head_preds = [
          predecessors(graphdef, name) + [name]
          for name in branch_head_names
      ]
      uniqs = []
      for n in range(len(branch_head_preds)):
          pres_preds = branch_head_preds[n]
          other_preds = (
              branch_head_preds[:n] + branch_head_preds[n + 1 :]
          )
          uniqs += [
              name
              for name in pres_preds
              if not any(name in others for others in other_preds)
          ]
      return uniqs
  
imports: import lucid.optvis.render
label_desc: Use image node_id 2 for calling a global function with example usage: get_branch_nodes(graphdef, concat_node) and returns: uniqs