code: def _environment_discovery_url():
      return os.environ.get(_DISCOVERY_SERVICE_URL_ENV_VARIABLE)
  
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 2 for calling a global function with example usage: _environment_discovery_url() and returns: os