code: def _get_tpu_name(tpu):
      if tpu:
          return tpu
  
      for e in [_GKE_ENV_VARIABLE, _DEFAULT_ENV_VARIABLE]:
          if e in os.environ:
              return os.environ[e]
      return None
  
imports: from concurrent import futures
  import datetime
  import json
  import logging
  import os
  import time
  import urllib
  from absl import flags
label_desc: Use image node_id 7 for calling a global function with example usage: _get_tpu_name(tpu) and returns: None, tpu, os