code: def get_metadata(key):
      return check_output(
          [
              "/usr/share/google/get_metadata_value",
              "attributes/{}".format(key),
          ]
      ).decode()
  
file_path: hail/hail/python/hailtop/hailctl/dataproc/resources/init_notebook.py
imports: import json
  import os
  import subprocess
  import sys
  import errno
  from subprocess import check_output
label_desc: Use image node_id 2 for calling a global function with example usage: get_metadata(key) and returns: check_output