code: def collate(samples):
      graphs, cat = map(list, zip(*samples))
      return dgl.batch(graphs), cat
  
imports: import argparse
  import os
  import time
  import urllib
  from functools import partial
  import dgl
  import numpy
  import torch
  import torch.nn
  import torch.nn.functional
  import torch.optim
  import tqdm
  from dgl.data.utils import download, get_download_dir
  from pointnet2_partseg import PointNet2MSGPartSeg, PointNet2SSGPartSeg
  from pointnet_partseg import PartSegLoss, PointNetPartSeg
  from ShapeNet import ShapeNet
  from torch.utils.data import DataLoader
label_desc: Use image node_id 1 for calling a global function with example usage: collate(samples) and returns: dgl,  cat