code: def decode_all(self, z):
      prob_adj = z @ z.t()
      return (prob_adj > 0).nonzero(as_tuple=False).t()
  
imports: import time
  import torch
  import torch.nn.functional
  import numpy
  import random
  from torch_geometric.datasets import Planetoid
  from torch_geometric.nn import GCNConv, GATConv, SAGEConv
  import torch_geometric.transforms
  from torch_geometric.utils import train_test_split_edges
  from torch_geometric.utils import negative_sampling
  import os.path
  from argparse import ArgumentParser, ArgumentDefaultsHelpFormatter
  from tqdm import tqdm
  from sklearn.metrics import roc_auc_score
label_desc: Use image node_id 4 for calling the GCN obj's underlying member method code with example usage: obj.decode_all(z) and returns: unknown