code: def track_time(batch_size):
      device = utils.get_bench_device()
      ds = dgl.data.QM7bDataset()
      # prepare graph
      graphs = []
      for graph in ds[0:batch_size][0]:
          g = graph.to(device)
          graphs.append(g)
  
      # dry run
      for i in range(10):
          g = dgl.batch(graphs)
  
      # timing
  
      with utils.Timer() as t:
          for i in range(100):
              g = dgl.batch(graphs)
  
      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