code: def get_session(config=None):
      """Get default session or create one with a given config"""
      sess = tf.get_default_session()
      if sess is None:
          sess = make_session(config=config, make_default=True)
      return sess
  
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 10 for calling a global function with example usage: get_session(config) and returns: sess