code: def log(s, nl=True):
      if bf.local_rank() != 0:
          return
      print(s, end="\n" if nl else "", flush=True)
  
file_path: bluefog/scripts/pytorch_opt_linear_speedup_test.py
imports: import argparse
  import timeit
  import time
  import os
  import numpy
  import torch
  import torch.backends.cudnn
  from torch import nn
  import torch.nn.functional
  import torch.optim
  import torch.utils.data.distributed
  from torchvision import models
  import bluefog.torch
  from bluefog.common import topology_util
label_desc: Use image node_id 3 for calling a global function with example usage: log(s, nl) without return types