code: def _maybe_tb_middleware(args):
      if args.dark_mode:
          from guild import tensorboard_util
  
          return tensorboard_util.dark_mode_middleware()
      return None
  
imports: import csv
  import logging
  import os
  import re
  import sys
  import time
  from guild import batch_util
  from guild import cli
  from guild import op_util
  from guild import run_util
  from guild import tfevent
  from guild import util
  from .None import runs_impl
label_desc: Use image node_id 19 for calling a global function with example usage: _maybe_tb_middleware(args) and returns: None, tensorboard_util