code: def traverse(item):
      """traverse the list or numpy"""
      if isinstance(item, list) or isinstance(item, np.ndarray):
          for i in iter(item):
              for j in traverse(i):
                  yield j
      else:
          yield item
  
imports: import sys
  import time
  import copy
  import warnings
  import numpy
  import pgl
  from pgl import graph_kernel
  from pgl.utils.logger import log
label_desc: Use image node_id 1 for calling a global function with example usage: traverse(item) without return types