code: def test_is_local(self):
      image_set = ImageSet.read(self.image_path)
      assert image_set.is_local() is True
      image_set = ImageSet.read(self.image_path, self.sc)
      assert image_set.is_local() is False
  
imports: import pytest
  import cv2
  from bigdl.dllib.nncontext import *
  from bigdl.dllib.feature.image import *
label_desc: Use image node_id 6 for calling the Test_Image_Set obj's underlying member method code with example usage: obj.test_is_local() without return types