code: def _gce_metadata_endpoint():
      endpoint = os.environ.get(_GCE_METADATA_ENDPOINT_ENV_VARIABLE)
      if not endpoint:
          endpoint = os.environ.get(
              _GCE_METADATA_URL_ENV_VARIABLE, "metadata.google.internal"
          )
      return "http://" + endpoint
  
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 3 for calling a global function with example usage: _gce_metadata_endpoint() and returns: unknown