code: def track_time(batch_size):
      device = utils.get_bench_device()
      ds = dgl.data.QM7bDataset()
      # prepare graph
      graphs = ds[0:batch_size][0]
      bg = dgl.batch(graphs).to(device)
  
      # dry run
      for i in range(10):
          glist = dgl.unbatch(bg)
  
      # timing
      with utils.Timer() as t:
          for i in range(100):
              glist = dgl.unbatch(bg)
  
      return t.elapsed_secs / 100
  
imports: import time
  import dgl
  import torch
  from ..None import utils
label_desc: Use image node_id 1 for calling a global function with example usage: track_time(batch_size) and returns: unknown