code: def get_session():
      global _session
  
      # Build/retrieve the session if it doesn't exist
      if _session is None:
          if tf.get_default_session() is not None:
              _session = tf.get_default_session()
          else:
              _session = tf.Session()
  
      return _session
  
label_desc: Use image node_id 1 for calling a global function with example usage: get_session() and returns: _session