code: def initialize():
      """Initialize all the uninitialized variables in the global scope."""
      new_variables = set(tf.global_variables()) - ALREADY_INITIALIZED
      get_session().run(tf.variables_initializer(new_variables))
  
      ALREADY_INITIALIZED.update(new_variables)
  
file_path: nni/nni/algorithms/hpo/ppo_tuner/util.py
imports: import os
  import random
  import multiprocessing
  import numpy
  import tensorflow.compat.v1
  from gym.spaces import Discrete, Box, MultiDiscrete
label_desc: Use image node_id 12 for calling a global function with example usage: initialize() without return types